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  • 1.
    Awe, Samuel A.
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E. W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Dahle, Arne
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Development of cast Al-Cu-Si ternary eutectic alloys for high temperature applications2016In: Proceedings and Abstracts Book of European Advanced Materials Congress, At Stockholm, Sweden / [ed] Ashutosh Tiwari, Linköping: VBRI Press , 2016Conference paper (Refereed)
  • 2.
    Awe, Samuel A.
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting. Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting. Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Lee, Young C.
    Dahle, Arne
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Development of new Al-Cu-Si alloys for high temperature performance2017In: Advanced Materials Letters, ISSN 0976-3961, E-ISSN 0976-397X, Vol. 8, no 6, p. 695-701Article in journal (Refereed)
    Abstract [en]

    In a quest to develop new light metal alloys that can perform excellently at elevated-temperatures (from 300°C to 400°C), a ternary eutectic Al-Cu-Si alloy was exploited to gain a deeper understanding of the alloy system and its suitability for high temperature applications. The alloys studied, with chemical composition of Al-27%Cu-5%Si (by weight percent) with Ni addition in the range of 0 to 1.5%wt, were cast in a rapid solidification casting technique. The solidification characteristics of the alloy was studied using the Thermo-Calc software. Microstructures were characterized in a scanning electron microscope coupled with energy dispersive spectrometry (SEM-EDS). Finally, the elevated-temperatures tensile properties of the alloys were investigated. Comparing the microstructures and mechanical properties of these Al-Cu-Si(-Ni) alloys with conventional Al-Si alloy A319, the refined microstructure with dispersed Ni intermetallic particles formed in the as-cast Al-Cu-Si(-Ni) alloys deliver improved elevated temperature properties. In particular, the yield strength and ultimate tensile strength of the new alloy with 1.5% Ni at 400?C were observed to be 220% and 309% higher, respectively, than for conventional A319 alloy.

  • 3.
    Belov, Ilja
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing - Surface technology.
    Jarfors, Anders E.W
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Simulering av prestandan hos rheogjutna kylflänsar2016In: Gjuteriet, ISSN 0017-0682, no 6, p. 49-Article in journal (Other academic)
  • 4.
    Belov, Ilja
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing - Surface technology.
    Payandeh, Mostafa
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Leisner, Peter
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing - Surface technology.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Wessen, Magnus
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Effect of fillets on heat transfer in a rheocast aluminium heatsink2016In: 2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE), IEEE, 2016Conference paper (Refereed)
    Abstract [en]

    The effect of fillets formed between the base and plate fins of rheocast aluminium heatsinks on the thermal resistance of the heatsinks has been quantified by simulation. Simulation methodology, including sequential optimization has been developed in order to determine hotspot distributions where the fillets have the maximum effect. Combination of different fillet dimensions with various base thickness levels and aluminium alloys having inhomogeneous thermal conductivity have been investigated. For the studied cases, the effect of fillets on heatsink thermal resistance differs from negligible to 6%. The results would guide thermal designers on contribution of fillets to the heat transfer in multi-fin heatsinks for natural convection.

  • 5. Bergman, A
    et al.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Liu, Zhen
    Fredriksson, Hasse
    Insitu fomation of carbide composites by liquid-solid reactions1992In: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 79/80, p. 213-234Article in journal (Refereed)
  • 6.
    Bi, G.
    et al.
    Singapore Institute of Manufacturing Technology.
    Ng, G. K. L.
    Singapore Institute of Manufacturing Technology.
    Teh, K. M.
    Singapore Institute of Manufacturing Technology.
    Jarfors, A. E. W.
    Singapore Institute of Manufacturing Technology.
    Feasibility study on the Laser Aided Additive Manufacturing of die inserts for liquid forging2010In: Materials & Design, ISSN 0261-3069, Vol. 31, no SUPPL. 1, p. S112-S116Article in journal (Refereed)
    Abstract [en]

    This paper reports the Laser Aided Additive Manufacturing of nickel-base alloy Nimonic 80A for the purpose of direct building of die inserts for liquid forging. Low porosity level of 0.01-0.04% with reasonable deposition rate was achieved. The micro-hardness showed very good homogeneity. Directionally solidified cellular micro-structure with an average size of 5Όm was observed. Very fine MC-type carbides were detected at the grain boundaries, which function as the strengthening phase of the alloy. © 2009 Elsevier Ltd.

  • 7.
    Bjurenstedt, Anton
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    On the complexity of the relationship between microstructure and tensile properties in cast aluminum2015In: International Journal of Modern Physics B, ISSN 0217-9792, Vol. 29, no 10-11, article id 1540011Article in journal (Refereed)
    Abstract [en]

    The relationship between microstructure and mechanical properties in cast aluminium alloys is very complex. This relationship is also strongly affected by the casting process and melt handling. In the current study the mechanical properties were investigated and correlated with microstructural features such as porosity, Fe-rich particles, SDAS, Si-length. Process quality measures such as bifilm index, density index, and sludge factor were also investigated. The aim of the work was to understand the critical interactions between material microstructure and process quality in the development of high performance materials.

  • 8.
    Bjurenstedt, Anton
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    The effects of Fe-particles on the tensile properties of Al-Si-Cu alloys2016In: Metals, ISSN 2075-4701, Vol. 6, no 12, article id 314Article in journal (Refereed)
    Abstract [en]

    The effect of Fe-rich particles has been a topic for discussion in the aluminum casting industry because of the negative impact they exert on the mechanical properties. However, there are still contradictions on the effects of various morphologies of Fe-particles. In this study, microstructural characterization of tensile tested samples has been performed to reveal how unmodified and modified Fe-rich particles impact on the tensile behavior. Analysis of additions of Fe modifiers such as Mn and Cr, showed higher amounts of primary Fe-rich particles (sludge) with increased porosity and, as result, degraded tensile properties. From the fracture analysis of tensile tested HIPed samples it could be concluded that the mechanical properties were mainly governed by the Fe-rich particles, which were fracturing through cleavage, not by the porosity.

  • 9.
    Borkar, Hemant
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    In-situ EBSD study of deformation behavior of Al-Si-Cu alloys during tensile testing2015In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 84, p. 36-47Article in journal (Refereed)
    Abstract [en]

    This study deals with the microstructural aspects of the deformation behavior in Al-Si-Cu alloy A380. This has been carried out with in-situ tensile testing coupled with EBSD analysis. The alloy specimens having different microstructures with two different secondary dendrite arm spacing (SDAS) of 9 µm and 27 µm were produced by the unique gradient solidification method. The study of misorientation distribution and texture evolution was performed with different tools in EBSD analysis. The texture was not significantly affected by deformation in both types of alloy specimens. With increase in the deformation, the microstructures are characterized by degradation of EBSD patterns and generation of substructures including low angle boundaries (LABs) and high angle boundaries (HABs). In both the microstructures with low and high SDAS, the boundaries were concentrated around eutectic phases; however this behavior was more pronounced at higher SDAS. The increase in the fraction of LABs with deformation was much higher in the microstructure with higher SDAS than with lower SDAS. This localized strain concentration was especially attributed to the large and elongated eutectic Si particles and Fe-rich intermetallics. The lower mechanical properties obtained at higher SDAS are the result of inhomogeneous strain distribution in the microstructure.

  • 10.
    Borkar, Hemant
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Microstructure analysis of Al-Si-Cu alloys prepared by gradient solidification technique2015In: International Journal of Modern Physics B, ISSN 0217-9792, Vol. 29, no 10-11, article id 1540015Article in journal (Refereed)
    Abstract [en]

    Al–Si–Cu alloys were cast with the unique gradient solidification technique to producealloys with two cooling rates corresponding to secondary dendrite arm spacing (SDAS) of ∼9 and ∼27 μm covering the microstructural fineness of common die cast components.The microstructure was studied with optical microscopy and scanning electronmicroscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and electronbackscattered diffraction (EBSD). The alloy with higher cooling rate, lower SDAS, hasa more homogeneous microstructure with well distributed network of eutectic and intermetallicphases. The results indicate the presence of Al–Fe–Si phases, Al–Cu phases andeutectic Si particles but their type, distribution and amount varies in the two alloys withdifferent SDAS. EBSD analysis was also performed to study the crystallographic orientationrelationships in the microstructure. One of the major highlights of this study is theunderstanding of the eutectic formation mechanism achieved by studying the orientationrelationships of the aluminum in the eutectic to the surrounding primary aluminumdendrites.

  • 11.
    Carlberg, Torbjörn
    et al.
    Mid Sweden University, Sundsvall, Sweden.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    On vertical drag defects formation during direct chill (DC) casting of aluminum billets2014In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 45, no 1, p. 175-181Article in journal (Refereed)
    Abstract [en]

    During air-slip direct chill casting of aluminum billets, one of the major defects occurring includes traces along the billet called vertical drags (VDs). If the VDs are too deep or too many, then they cause scraping of the billets. As in the subsequent extrusion process, the surface quality is known to impair both the productivity and quality of the profiles. In cast-house practice, many theories circulate about the causes of VD defects and how to avoid them, but in the literature, no thorough treatments have been made to explain this phenomenon. In the current study, the outer appearance, structure around, and compositions at the defects are analyzed. A theory for the formation of the defects, their cause, and how their appearance is coupled to different alloy types is presented. The segregation in the vicinity of the defects is discussed based on deformation of semisolid materials and coupled to Reynolds dilatancy ingranular materials. The theory can explain differences between 6063 and 6005 alloys.

  • 12.
    Ceschini, Lorella
    et al.
    Department of Industrial Engineering (DIN), Alma Mater Studiorum–University of Bologna, Bologna, Italy.
    Dahle, Arne
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Gupta, Manoj
    Department of Mechanical Engineering, National University of Singapore, Singapore.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jayalakshmi, S.
    Department of Mechanical Engineering, Bannari Amman Institute of Technology (BIT), Sathyamangalam, India.
    Morri, Alessandro
    Interdepartmental Center for Industrial Research-Advanced Mechanics and Materials (CIRI-MAM), Alma Mater Studiorum–University of Bologna, Bologna, Italy.
    Rotundo, Fabio
    Interdepartmental Center for Industrial Research-Advanced Mechanics and Materials (CIRI-MAM), Alma Mater Studiorum–University of Bologna, Bologna, Italy.
    Toschi, Stefania
    Department of Industrial Engineering (DIN), Alma Mater Studiorum–University of Bologna, Bologna, Italy.
    Singh, R. Arvind
    Department of Aeronautical Engineering, Bannari Amman Institute of Technology (BIT), Sathyamangalam, India.
    Aluminum and Magnesium Metal Matrix Nanocomposites2017Book (Other academic)
    Abstract [en]

    The book looks into the recent advances in the ex-situ production routes and properties of aluminum and magnesium based metal matrix nanocomposites (MMNCs), produced either by liquid or semi-solid state methods. It comprehensively summarizes work done in the last 10 years including the mechanical properties of different matrix/nanoreinforcement systems. The book also addresses future research direction, steps taken and missing developments to achieve the full industrial exploitation of such composites. The content of the book appeals to researchers and industrial practitioners in the area of materials development for metal matrix nanocomposites and its applications.

  • 13.
    Ceschini, Lorella
    et al.
    Department of Industrial Engineering (DIN), Alma Mater Studiorum-University of Bologna, V.le Risorgimento 4, 40136 Bologna, Italy.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Morri, A.
    Department of Industrial Engineering (DIN), Alma Mater Studiorum-University of Bologna, V.le Risorgimento 4, 40136 Bologna, Italy.
    Rotundo, F.
    Interdepartmental Center for Industrial Research-Advanced Mechanics and Materials (CIRIMAM), Alma Mater Studiorum-University of Bologna, V.le Risorgimento 4, 40136 Bologna, Italy.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Toschi, S.
    Department of Industrial Engineering (DIN), Alma Mater Studiorum-University of Bologna, V.le Risorgimento 4, 40136 Bologna, Italy.
    High temperature tensile behaviour of the A354 aluminum alloy2014In: Materials Science Forum, Vol. 794-796, p. 443-448Article in journal (Refereed)
    Abstract [en]

    The high temperature tensile behaviour of the A354 casting aluminum alloy was investigated also evaluating the influence of secondary dendrite arm spacing (SDAS). Cast specimens were produced through a gradient solidification equipment, obtaining two different classes of SDAS, namely 20-25 µm (fine microstructure) and 40-50 µm (coarse microstructure). After hot isostatic pressing and T6 heat treatment, the samples underwent mechanical characterization both at room and high temperature (200 °C). Results of tensile tests and hardness measurements were related to the microstructural features and fractographic characterization, in order to investigate the effect of microstructure and high temperature exposure on the mechanical behaviour of the alloy.

  • 14.
    Christina, Keller
    et al.
    Jönköping University, Jönköping International Business School, JIBS, Informatics.
    Wass, Sofie
    Jönköping University, Jönköping International Business School, JIBS, Informatics.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Zetterlind, Madelene
    Jönköping University, School of Engineering, JTH, Industrial Engineering and Management.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Vomacka, Peter
    Hackås Precision Foundry.
    Structured knowledge transfer through online education: Mutual benefits for academia and industry2016Conference paper (Refereed)
    Abstract [en]

    Scientists are required to disseminate the results of research to the society and companies participating in research projects. The dissemination procedure normally consists of seminars, scientific and layman journal contributions, and conferences that generally are not flexible and timely enought to capture industrial needs. In an effort to accelerate knowledge transfer and technology implementation to sustain and improve competitiveness, Jönköping University has developed a one-year online master programme in cast metals and processes in collaboration with the industry. The collaboration includes development of the curriculum, case studies, lectures and study visits. To explore the development process, we performed interviews and a survey with participating students/professionals, teachers and industrial partners. Our results show that a profound two-way knowledge transfer took place, and that course content and teaching were highly relevant to the industry. Furthermore, industry and academia engaged in new joint research collaborations. Consequently, we hypothesize that the procedure for structured knowledge transfer can be implemented in materials education at advanced level to foster engagement between university, industry and society.

  • 15.
    Danno, A.
    et al.
    Singapore Institute of Manufacturing Technology.
    Wong, C. C.
    Singapore Institute of Manufacturing Technology.
    Tong, S.
    Singapore Institute of Manufacturing Technology.
    Jarfors, A.
    Singapore Institute of Manufacturing Technology.
    Nishino, K.
    Toyota Central Research and Development Labs. Inc., Nagakute, Aichi, Japan.
    Furuta, T.
    Toyota Central Research and Development Labs. Inc., Nagakute, Aichi, Japan.
    Effect of cold severe deformation by multi directional forging on elastic modulus of multi functional Ti+25mol% (Ta,Nb,V)+(Zr,Hr,O) alloy2010In: Materials & Design, ISSN 0261-3069, Vol. 31, no SUPPL. 1, p. S61-S65Article in journal (Refereed)
    Abstract [en]

    A new and unique beta-titanium alloy (Ti. +. 25. mol% (Ta,Nb,V). +. (Zr,Hr,O) has interesting properties such as low elastic modulus, high strength and high elastic deformability as well as Invar and Elinvar properties. These properties have been successfully realized for the round wire or rods by cold working process but not enough for the sheet made by the cold rolling.To improve the mechanical properties of the alloy sheet, the effect of cold severe deformation on the elastic modulus and microstructure of the alloy sheet was experimentally investigated. The samples were processed using the multi directional forging (MDF) and cold plain rolling.The elastic modulus of the alloy sheet which was cold rolled after MDF was lower than that of cold rolled sheet without MDF. The severe cold plastic deformation by MDF was also effective for obtaining isotropic elastic modulus and very fine grain size (∌1ÎŒm) of sheet after plain rolling. The prototype sheet with low elastic modulus (60-65. GPa), high strength (1100. MPa) and high ductility (total elongation more than 10%) was successfully made in the laboratory test by combining MDF and plain rolling at room temperature. © 2009 Elsevier Ltd.

  • 16.
    Ding, X.
    et al.
    Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, Singapore 638075, Singapore.
    Jarfors, A. E. W.
    Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, Singapore 638075, Singapore.
    Lim, G. C.
    Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, Singapore 638075, Singapore.
    Shaw, K. C.
    Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, Singapore 638075, Singapore.
    Liu, Y. C.
    Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, Singapore 638075, Singapore.
    Tang, L. J.
    Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore.
    A study of the cutting performance of poly-crystalline oxygen free copper with single crystalline diamond micro-tools2012In: Precision engineering, ISSN 0141-6359, E-ISSN 1873-2372, Vol. 36, no 1, p. 141-152Article in journal (Refereed)
    Abstract [en]

    A study was carried out to investigate the crystallographic effects on the performance of cutting poly-crystalline oxygen free copper C10200 (OFC) with single crystalline diamond (SCD) micro-tools. At both large cutting depth and cross-feed rate, as the micro-tool traversed a grain with a crystallographic orientation less favorable for a stable machining process, the work material in front of the rake face was found to be severely deformed. This may lead to a reduced shear angle, thick chip, striation at the back of the chip, high cutting forces, degraded machined surface and the possibility of burr formation. The results showed minimal variations in the machined surface integrity and cutting forces compared to cut amorphous NiP plating with micro-tools. For a high cutting depth, burrs were also observed due to material deformation and pile-up occurring at the groove edges since the localized stress probably built up in front of the rake face. Cutting strategies were demonstrated to improve the performance of cutting OFC with micro-tools and to generate high aspect ratio micro-pillar arrays.

  • 17.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Ghassemali, Ehsan
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Microstructural Scale Effects on Thermal Expansion Behaviour of Cast AZ91D2015In: Magnesium Technology 2015 - TMS 2015 144th Annual Meeting and Exhibition, Orlando, March 15-19, 2015, Hoboken: John Wiley & Sons, 2015, p. 361-365Conference paper (Refereed)
    Abstract [en]

    The effect of microstructure on thermal expansion of AZ91D cast alloy was studied. Samples with equiaxed grains and a controlled secondary dendrite arm spacing (SDAS) were fabricated using gradient solidification. SDAS was chosen to represent the range ofmicrostructural scale found in sand castings down to that of high pressure die casting. Optical microscopy and electron backscatter diffraction (EBSD) were used for microstructural characterization. The relation between thermal expansion and microstructuralscale of existing phases precipitated, in particular grain size, SDAS and fraction of Mg17Al12 was analyzed.

  • 18.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Effect of Mg17Al12 content on mechanical properties of AZ91D cast alloyIn: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456Article in journal (Refereed)
  • 19.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Effect of Mg17Al12 Fraction on Mechanical Properties of Mg-9%Al-1%Zn Cast Alloy2016In: Metals, ISSN 2075-4701, Vol. 6, no 10, article id 251Article in journal (Refereed)
    Abstract [en]

    In the current study it was observed that the offset yield point of Mg-9%Al-1%Zn alloy was strongly influenced by the connectivity of Mg17Al12. It was suggested that an increase in the fraction of Mg17Al12 from 8% to 11% could lead to the formation of a Mg17Al12 network which resulted in a higher offset yield point. In addition, it was observed that elongation to failure of the Mg-9%Al-1%Zn alloy strongly depended on the fraction of Mg17Al12. Moreover, the apparent toughness showed a strong inverse relation to the secondary dendrite arm spacing. This approach might be extended to forecast the behavior in other magnesium alloys forming a network of the Mg-Al phase.

  • 20.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Effect of process parameters on distortion and residual stress in high pressure die cast AZ91D components after shot peening and paintingManuscript (preprint) (Other academic)
  • 21.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH, Mechanical Engineering. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Effect of process parameters on distortion and residual stress of high-pressure die-cast AZ91D components2018In: International Journal of metalcasting, ISSN 1939-5981, E-ISSN 2163-3193, Vol. 12, no 3, p. 487-497Article in journal (Refereed)
    Abstract [en]

    This paper presents a study of distortion and residual stress within a high-pressure die-cast AZ91D component, cast under different processing conditions. The influence of process parameters, i.e., die temperature, cooling time, intensification pressure and first-phase injection speeds, was examined. Distortions were measured using the in-house standard analog quality control fixture. Residual stress depth profiles were measured using a prism hole-drilling method. It was found that the most important process parameter affecting the distortion was intensification pressure and the second most important was temperature difference between the two die halves (fixed and moving side). Tensile residual stresses were found very near the surface. Increasing the intensification pressure resulted in an increased level of tensile residual stresses.

  • 22.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Effects of microstructure on deformation behaviour of AZ91D cast alloy2014In: TMS 2014 Annual Meeting Supplemental Proceedings TMS, The Minerals, Metals & Materials Society, San Diego, February 16-20, 2014, John Wiley & Sons, 2014, p. 565-572Conference paper (Refereed)
    Abstract [en]

    The deformation behavior of AZ91D cast magnesium alloy was investigated using uniaxial tensile tests from room temperature up to 190°C and strain rates from 0.0001 up to 0.1 1/s. In present work gradient solidification in a Bridgeman furnace was employed to study the effect of initial microstructure on the tensile mechanical response of the AZ91D alloy. The furnace drawing rate was varied from minimum 0.3 to maximum 6 mm/s, which yielded a variation of SDAS from 4.2 up to 25 as well as a variation of the fraction of the γ -phase (Mg17Al12),. The effects of microstructural parameters such as SDAS and γ -phase morphology on the yield strength (YS), ultimate tensile strength (UTS) and hardening were investigated

  • 23.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Svoboda, A.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Ghassemali, Ehsan
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Lindgren, L.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Modeling the Deformation Behavior of As-Cast AZ1D Including the Effect of The Cast Microstructure2017In: Proceedings of PLASTICITY ’17: The Twenty Third International Conference on Plasticity, Damage, and Fracture, 2017, p. 37-39Conference paper (Refereed)
  • 24.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Svoboda, Ales
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Ghassemali, Ehsan
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Lindgren, L.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Dislocation Density Model for Flow Stress of AZ91D Magnesium Alloy-Effect of Temperature and MicrostructureIn: International journal of plasticity, ISSN 0749-6419, E-ISSN 1879-2154Article in journal (Refereed)
  • 25.
    Dini, Hoda
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Svoboda, Ales
    Department of Materials and Manufacturing, School of Engineering, Jönköping University, Jönköping, Sweden.
    Andersson, Nils-Eric
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Ghassemali, Ehsan
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Lindgren, Lars-Erik
    Division of Mechanics of Solid Materials, Luleå University of Technology, Luleå, Sweden.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Optimization and validation of a dislocation density based constitutive model for as-cast Mg-9%Al-1%Zn2018In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 710, p. 17-26Article in journal (Refereed)
    Abstract [en]

    A dislocation density-based constitutive model, including effects of microstructure scale and temperature, was calibrated to predict flow stress of an as-cast AZ91D (Mg-9%Al-1%Zn) alloy. Tensile stress-strain data, for strain rates from 10-4 up to 10-1 s-1 and temperatures from room temperature up to 190 °C were used for model calibration. The used model accounts for the interaction of various microstructure features with dislocations and thereby on the plastic properties. It was shown that the Secondary Dendrite Arm Spacing (SDAS) size was appropriate as an initial characteristic microstructural scale input to the model. However, as strain increased the influence of subcells size and total dislocation density dominated the flow stress. The calibrated temperature-dependent parameters were validated through a correlation between microstructure and the physics of the deforming alloy. The model was validated by comparison with dislocation density obtained by using Electron Backscattered Diffraction (EBSD) technique.

  • 26.
    Diószegi, Attila
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Diaconu, Lucian VasileJönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting. Jönköping University, School of Engineering, JTH, Materials and Manufacturing.Jarfors, Anders E.W.Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting. Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Science and Processing of Cast Iron XI2018Conference proceedings (editor) (Refereed)
    Abstract [en]

    The goal of this book is to present for readers the articles from the 11th International Symposium on the Science and Processing of Cast Iron that was held in September 2017 in Jönköping, Sweden. The content of the book reflects the state of the art, research and development tendencies of cast iron as the main engineering cast material also in the 21st century.

  • 27.
    Ekbom, L. B.
    et al.
    Department of Casting of Metals, Royal Institute of Technology, Stockholm, Sweden.
    Lei, B.
    Department of Casting of Metals, Royal Institute of Technology, Stockholm, Sweden.
    Eliasson, A.
    Department of Casting of Metals, Royal Institute of Technology, Stockholm, Sweden.
    Jarfors, A.
    Department of Casting of Metals, Royal Institute of Technology, Stockholm, Sweden.
    Liquid phase sintering of tungsten composites under microgravity: Influence of liquid/particle surface energy1991In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 11, no 7, p. 331-335Article in journal (Refereed)
    Abstract [en]

    Tungsten-nickel-iron heavy metals are fabricated from powders by liquid phase sintering. A study of the sintering mechanism of heavy metals with a low amount of tungsten particles can, depending on sedimentation, only be done under microgravity. At two earlier Texus flights, No 10 & 19, the growth rate and agglomeration of tungsten particles under microgravity were compared to that under gravity and sedimentation. During the first minute sintering period the particles in the agglomerates were separated and the particle distribution became even. The particle growth rate under microgravity, initially high, is slowing down. At further studies under gravity the influence of surface energy between the liquid phase and the tungsten particles have been investigated. Additions of sulphur and cobolt were used to decrease the surface energy and the use of nickel without iron to increase the energy. At a high surface energy the growth rate increases due to increased driving force. Preliminary results from the Texus 26 flight (April 90) are included. © 1991.

  • 28.
    El-Mahallawy, N.
    et al.
    Ain-Sham University, Faculty of Engineering, Cairo, Egypt.
    Taha, M. A.
    Ain-Sham University, Faculty of Engineering, Cairo, Egypt.
    Jarfors, A. E. W.
    Royal Institute of Technology, Department of Materials Processing, Stockholm, Sweden.
    Fredriksson, H.
    Royal Institute of Technology, Department of Materials Processing, Stockholm, Sweden.
    On the reaction between aluminum, K2TiF6 and KBF41999In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 292, no 1-2, p. 221-229Article in journal (Refereed)
    Abstract [en]

    The reaction between molten Al and KBF4 and K2TiF6 was analyzed. Additions of the two salts separately, consecutively and simultaneously were made at 800 and 1000 °C. The phases formed were identified and their morphology investigated. When adding K2TiF6 emulsification of the salt occurs. Residual salt containing K, Ti, Al and O was found in addition to slag containing K, Al and O. In an emulsified region, a new globular morphology of Al3Ti-type was found. No evidence of emulsification of KBF4 was found. This implies that the two salts react individually with Al. A new morphology of AlB2, in the form of thin plates, formed presumably at the salt/aluminum interface, was also found.

  • 29.
    Esmaily, M.
    et al.
    Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Shahabi-Navid, M.
    Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Mortazavi, N.
    Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Svensson, J. E.
    Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Halvarsson, M.
    Wessen, M.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, A. E. W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Johansson, L. G.
    Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Microstructural characterization of the Mg-Al alloy AM50 produced by a newly developed rheo-casting process2014In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 95, p. 50-64Article in journal (Refereed)
    Abstract [en]

    The microstructure of rheo-cast Mg-Al alloy AM50 produced by the RheoMetal process is investigated and compared with the same alloy produced by conventional high pressure die casting. The size and arrangement of microstructural constituents and pores are characterized quantitatively using image analyzing techniques. The nearest neighbor distribution of the intermetallic particles is determined. The area fraction of porosity in rheo-cast AM50 is about half that found in the high pressure die cast alloy. In rheo-cast material, the distribution of p phase (Mg17Al12) is relatively uniform throughout the cast. In contrast, the beta phase particles tend to form macroscopic agglomerates in high pressure die cast material. The externally solidified grains in the rheo-cast material exhibit a smaller aluminum gradient than in the high pressure die cast alloy. This indicates that the solidification of the rheo-cast material is closer to equilibrium. (C) 2014 Elsevier Inc. All rights reserved.

  • 30.
    Esmaily, Mohsen
    et al.
    Chalmers University of Technology.
    Mortazavi, N.
    Chalmers University of Technology.
    Svensson, Jan-Erik
    Chalmers University of Technology.
    Halvarsson, Mats
    Chalmers University of Technology.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Wessén, Magnus
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Arrabal, R.
    Universidad Complutense, Spain.
    Johansson, Lars-Gunnar
    Chalmers University of Technology.
    On the microstructure and corrosion behavior of AZ91/SiC composites produced by rheocasting2016In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 180, p. 29-37Article in journal (Refereed)
    Abstract [en]

    The corrosion behavior of magnesium-aluminum (Mg-Al) alloy AM50 produced by a rheocasting (RC) technique was examined in the presence and absence of CO2 at three temperatures -4, 4 and 22 degrees C. The slurry preparation in the RC material was performed with the newly developed RheoMetal process. For reference, 99.97% Mg was included in the corrosion exposures. The influence of the microstructure on the atmospheric corrosion of alloy AM50 produced by RC and high pressure die casting (HPDC) was investigated. The RC AM50 alloy showed better corrosion resistance than HPDC AM50 in all the exposure environments studied. For both materials, there was a strong positive correlation between temperature and the atmospheric corrosion rate. The superior atmospheric corrosion behavior of RC AM50 compared to HPDC AM50 is carefully discussed in relation to differences in the as-cast microstructure. This study demonstrates that producing the alloy AM50 by this type of RC technique opens the door to Mg-Al alloys as a promising candidate for various applications where corrosion resistance is of importance.

  • 31.
    Esmaily, Mohsen
    et al.
    Chalmers University of Technology.
    Mortazavi, Nooshin
    Chalmers University of Technology.
    Svensson, Jan-Erik
    Chalmers University of Technology.
    Halvarsson, Mats
    Chalmers University of Technology.
    Wessén, Magnus
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Johansson, Lars-Gunnar
    Chalmers University of Technology.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    A new semi-solid casting technique for fabricating SiC-reinforced Mg alloys matrix composites2016In: Composites Part B: Engineering, ISSN 1359-8368, E-ISSN 1879-1069, Vol. 94, p. 176-189Article in journal (Refereed)
    Abstract [en]

    The capability of the newly developed rheocasting (RC) technique in combination with the RheoMetal process for producing SiC particulate-reinforced AM50 and AZ91D matrix composites (Mg-based MMCs) was investigated. The quality of the MMCs was studied by analyzing the fraction of casting pores, number density of SiC clusters and the uniformity of SiC particles. Solid fraction, particle size and oxidation of SiC particles had strong impacts on the overall quality of the MMCs. The MMCs produced by 40% solid fraction and oxidized micron-sized SiC particles exhibited an excellent casting quality. A low-quality MMC was obtained when non-oxidized sub-micron sized SiC particles were employed. The results showed the formation of various types intermetallic particles and carbides such as MgO, Mg2Si, Al2MgC2, Mg2C3, Al4C3 as the interfacial reaction products of SiC/Mg alloy’s melts. Mg hydride (α-MgH2) was also identified in inter-dendritic regions of the MMCs for the first time.

  • 32.
    Esmaily, Mohsen
    et al.
    Chalmers University of Technology.
    Mortazavi, Seyedeh Nooshin
    Chalmers University of Technology,.
    Svensson, Jan-Erik
    University of Technology.
    Halvarsson, Mats
    Chalmers University of Technology.
    Blücher, Daniel Bengtsson
    SINTEF Materials and Chemistry.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Wessén, Magnus
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Johansson, Lars-Gunnar
    Chalmers University of Technology.
    Atmospheric Corrosion of Mg Alloy AZ91D Fabricated by aSemi-Solid Casting Technique: The Influence of Microstructure2015In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 162, no 7, p. C311-C321Article in journal (Refereed)
    Abstract [en]

    The atmospheric corrosion behavior of alloy AZ91D produced by a semi-solid metal (SSM) technique and by conventional high pressure die casting (HPDC) was investigated for up to 1176 hours in the laboratory. Alloy AZ91D in the SSM state was fabricated using a rheocasting (RC) technique in which the slurry was prepared by the RheoMetal process. Exposures were performed in 95% RH air at 22 and 4 degrees C. The RC alloy AZ91D exhibited significantly better corrosion resistance than the HPDC material at two temperatures studied. The effect of casting technology on corrosion is explained in terms of the microstructural differences between the materials. For example, the larger number density of cathodic beta phase particles in the HPDC material initially causes relatively rapid corrosion compared to the RC material. During later stages of corrosion, the more network-like beta phase particles in the RC alloy act as a corrosion barrier, further improving the relative corrosion resistance of the RC material.

  • 33.
    Esmaily, Mohsen
    et al.
    Chalmers University of Technology.
    Mortazavi, Seyedeh
    Chalmers University of Technology.
    Shahabi-Navid, Mehrdad
    Chalmers University of Technology.
    Svensson, Jan-Erik
    University of Technology.
    Halvarsson, Mats
    Chalmers University of Technology.
    Nyborg, Lars
    Chalmers University of Technology.
    Wessén, Magnus
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Johansson, Lars-Gunnar
    Chalmers University of Technology.
    Effect of Rheocasting on Corrosion of AM50 Mg Alloy2015In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 162, no 3, p. C85-C95Article in journal (Refereed)
    Abstract [en]

    The corrosion behavior of magnesium-aluminum (Mg-Al) alloy AM50 produced by a rheocasting (RC) technique was examined in the presence and absence of CO2 at three temperatures -4, 4 and 22 degrees C. The slurry preparation in the RC material was performed with the newly developed RheoMetal process. For reference, 99.97% Mg was included in the corrosion exposures. The influence of the microstructure on the atmospheric corrosion of alloy AM50 produced by RC and high pressure die casting (HPDC) was investigated. The RC AM50 alloy showed better corrosion resistance than HPDC AM50 in all the exposure environments studied. For both materials, there was a strong positive correlation between temperature and the atmospheric corrosion rate. The superior atmospheric corrosion behavior of RC AM50 compared to HPDC AM50 is carefully discussed in relation to differences in the as-cast microstructure. This study demonstrates that producing the alloy AM50 by this type of RC technique opens the door to Mg-Al alloys as a promising candidate for various applications where corrosion resistance is of importance.

  • 34.
    Fjellstedt, J.
    et al.
    Division of Casting of Metals, KTH, Stockholm, Sweden.
    Jarfors, A. E. W.
    Division of Casting of Metals, KTH, Stockholm, Sweden.
    Experimental and theoretical study of the Al-rich corner in the ternary Al-Ti-B system and reassessment of the Al-rich side of the binary Al-B phase diagram2001In: Zeitschrift für Metallkunde, ISSN 0044-3093, Vol. 92, no 6, p. 563-571Article in journal (Refereed)
    Abstract [en]

    The phase relations on the B-rich side of stoichiometric TiB2 were experimentally studied. It was found that a peritectic four-phase reaction liquid + AlB12 ⇔ AlB2 + TiB2 occurs at a temperature between 1073 and 1173 K. Part of the Al-rich corner of the Al-Ti-B phase diagram was calculated and isothermal sections at 973, 1073, 1173 and 1273 K are presented. The peritectic four-phase reaction was calculated to occur at 1150 K in agreement with the experimental results. The Al-rich part of the binary Al-B system was reassessed. A eutectic reaction liquid ⇔ AlB2 + (Al) was confirmed to occur at 932.9 K and 0.055 at.% B and a peritectic reaction liquid +AlB12 ⇔ AlB2 concluded to happen at 1150 K (slightly above the four-phase reaction) and 0.60 at.% B, which is at a lower temperature than previously reported.

  • 35.
    Fjellstedt, J.
    et al.
    Outokumpu Copper R and D, Västerås, Sweden.
    Jarfors, A. E. W.
    Corrosion and Metals Research Institute, Stockholm, Sweden.
    On the precipitation of TiB2 in aluminum melts from the reaction with KBF4 and K2TiF62005In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 413-414, p. 527-532Article in journal (Refereed)
    Abstract [en]

    The divergent reaction between Al and the two salts K2TiF6 and KBF4 are used in the manufacturing of Al-Ti-B master alloys for grain refinement. It is also possible to use the same reaction to make aluminum based metal matrix composites. The formation sequence of TiB2 from the reaction with K2TiF6 and KBF4 is discussed in the view of the formation of a salt/metal emulsion and agglomeration. The highly exothermic reaction with K2TiF6 will aid the formation of an emulsion and Al3Ti form that in a subsequent step transforms into TiB2. It will also support high element transfer efficiency. The reaction with KBF4 causes less heat to evolve and the tendency towards formation of an emulsion and thus lower transfer efficiency resulting in a sluggish formation of AlB2. Simultaneous additions of K2TiF6 and KBF4 increase the transfer efficiency but will cause the formation of stringer defects in a layered structure. © 2005 Elsevier B.V. All rights reserved.

  • 36.
    Fjellstedt, J.
    et al.
    Royal Institute of Technology, Division of Metals Casting, Stockholm, Sweden.
    Jarfors, A. E. W.
    Royal Institute of Technology, Division of Metals Casting, Stockholm, Sweden.
    El-Benawy, T.
    Royal Institute of Technology, Division of Metals Casting, Stockholm, Sweden.
    Experimental investigation and thermodynamic assessment of the Al-rich side of the Al-B system2001In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Materials & Design, ISSN 0261-3069, Vol. 22, no 6, p. 443-449Article in journal (Refereed)
    Abstract [en]

    The phase relations in the Al-Ti-B system are of great importance for the manufacturing of Al/TiB2 composites. To describe the phase relations, the relations in the binaries Al-B, Ti-B and Al-Ti must be known. The description of the binary Al-B system has been found to be poor. The Al-rich side of the Al-B phase diagram was studied using DSC, on alloys ranging from 0.5 up to 6.4 at ·% B. The Al-rich part of the phase diagram was assessed using the experimental data and data found in the literature. The eutectic temperature was found to agree well with the literature. However, the peritectic temperature was found to be 914°C. Above the peritectic temperature a metastable primary precipitation of AlB2 below the AlB12 liquidus line was suggested. This type of degenerate peritectic reaction is similar to what has been found in Fe-based materials. This behaviour also explains the difficulty in the determination of the peritectic point by experimental means. © 2001 Elsevier Science Ltd. All rights reserved.

  • 37.
    Fjellstedt, J.
    et al.
    Royal Institute of Technology, Department of Materials Processing, Casting of Metals, Stockholm, Sweden.
    Jarfors, A. E. W.
    Royal Institute of Technology, Department of Materials Processing, Casting of Metals, Stockholm, Sweden.
    Svendsen, L.
    Royal Institute of Technology, Department of Materials Processing, Casting of Metals, Stockholm, Sweden.
    Experimental analysis of the intermediary phases AlB2, AlB12 and TiB2 in the Al-B and Al-Ti-B systems1999In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 283, no 1-2, p. 192-197Article in journal (Refereed)
    Abstract [en]

    The phases AlB2, AlB12 and TiB2 were studied in Al-rich Al-B and Al-Ti-B alloys produced by several different sample fabrication methods. The samples were examined using light optical microscopy (LOM), energy dispersive X-ray spectroscopic analysis (EDS) and X-ray diffraction analysis (XRD). The results indicate that only a limited solubility of Al in TiB2 and Ti in AlB2 exists, hence a continuous compound (Al,Ti)B2 is not stable. © 1999 Elsevier Science S.A. All rights reserved.

  • 38.
    Fu, X. L.
    et al.
    Sch.of Mech. and Aerospace Eng, Nanyang Technological University, Singapore.
    Tan, M. J.
    Sch.of Mech. and Aerospace Eng, Nanyang Technological University, Singapore.
    Jarfors, A. E. W.
    Sch.of Mech. and Aerospace Eng, Nanyang Technological University, Singapore.
    Gupta, M.
    Dept. of Mechanical Engineering, National University of Singapore.
    Processing and properties of amorphous magnesium-based eco-materials2011In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 695, p. 186-189Article in journal (Refereed)
    Abstract [en]

    Magnesium alloys are the lightest known structural material and have been very attractive for usage in marine and transportation industry (for its weight savings and payload increase), and also for its portability in hand-held devices. It is recyclable and one of the most abundant metal. Lately, it has gained attention for its biocompatibility, and also its biodegradable properties depending on the alloying elements. They can be used as a biomaterial in various applications from heart stents to implant screws and fixtures. In this work, amorphous magnesium alloys have been processed, based on its glass forming ability, by various techniques in order to obtain its amorphous state, and the microstructure are characterized by thermal analysis, X-ray diffraction and electron microscopy. Their mechanical properties are also presented. High temperature tensile tests show similar strength to room temperature strength, while the total failure strain is significantly increased from around 0.5% to 10%.

  • 39.
    Ghasemi, Rohollah
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Elmquist, Lennart
    SinterCast AB, Sweden.
    Ghassemali, Ehsan
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E. W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Effect of interaction between lamellar graphite and cat-fines on tribological behaviour of cast iron under abrasion2015In: Proceeding of ITC, 2015Conference paper (Refereed)
  • 40.
    Ghasemi, Rohollah
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Elmquist, Lennart
    Swerea SWECAST, Jönköping, Sweden.
    Ghassemali, Ehsan
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Salomonsson, Kent
    Jönköping University, School of Engineering, JTH, Product Development. Jönköping University, School of Engineering, JTH. Research area Product Development - Simulation and Optimization.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Abrasion resistance of lamellar graphite iron: Interaction between microstructure and abrasive particles2018In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 120, p. 465-475Article in journal (Refereed)
    Abstract [en]

    This study focuses on abrasion resistance of Lamellar Graphite Iron (LGI) using microscratch test under constant and progressive load conditions. The interactions between a semi-spherical abrasive particle, cast iron matrix and graphite lamellas were physically simulated using a sphero-conical indenter. The produced scratches were analysed using LOM and SEM to scrutinise the effect of normal load on resulting scratch depth, width, frictional force, friction coefficient and deformation mechanism of matrix during scratching. Results showed a significant matrix deformation, and change both in frictional force and friction coefficient by increase of scratch load. Furthermore, it was shown how abrasive particles might produce deep scratches with severe matrix deformation which could result in graphite lamella's coverage and thereby deteriorate LGI's abrasion resistance.

    The full text will be freely available from 2020-01-04 00:00
  • 41.
    Ghasemi, Rohollah
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Elmquist, Lennart
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Svensson, Henrik
    Swerea SWECAST AB, Materials and Process Development P.O. Box 2033, SE-550 02 Jönköping, Sweden.
    König, Mathias
    Scania CV AB, Materials Technology, SE-151 87 Södertälje, Sweden.
    E. W. Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Mechanical properties of solid solution strengthened CGI2014Conference paper (Refereed)
    Abstract [en]

    The development of high-performing components is crucial in applications such as heavy vehicleautomotive powertrains. In these applications, strength, weight and thermal conductivity isessential properties. Key materials that may fulfil these requirements include cast irons of differentgrades where in terms of manufacturability and in particular, machinability pearlitic grades aredifficult due to hardness variation, where a fully ferritic matrix would provide an advantage. Toachieve maximum strength a fully ferritic and solid solution strengthened compacted graphite iron(CGI) would provide an interesting alternative to the automotive industry. In the current study, theeffect of Si level on mechanical properties in a fully ferritic material was investigated. The influenceof section thickness on tensile properties and hardness was investigated. The resulting materialwas fully ferritic with limited pearlite content. Section thickness influence on nodularity and hencethe mechanical properties were also investigated.

  • 42.
    Ghasemi, Rohollah
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Elmquist, Lennart
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Svensson, Henrik
    Swerea SWECAST AB, Materials and Process Development, Jönköping, Sweden.
    König, Mathias
    Scania CV AB, Materials Technology, Södertälje, Sweden.
    Jarfors, Anders E. W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Mechanical properties of solid solution-strengthened CGI2016In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 29, no 1-2, p. 98-105Article in journal (Refereed)
    Abstract [en]

    Despite the increased usage of pearlitic compacted graphite iron (CGI) in heavy vehicle engines, poor machinability of this material remains as one of the main technical challenges as compared to conventional lamellar iron. To minimise the machining cost, it is believed that solution-strengthened CGI material with a ferritic matrix could bring an advantage. The present study focuses on the effect of solution strengthening of silicon and section thickness on tensile, microstructure and hardness properties of high-Si CGI materials. To do so, plates with thicknesses from 7 to 75 mm were cast with three different target silicon levels 3.7, 4.0 and 4.5 wt%. For all Si levels, the microstructure was ferritic with a very limited pearlite content. The highest nodularity was observed in 7 and 15 mm plate sections, respectively, however, it decreased as the plate thickness increased. Moreover, increasing Si content to 4.5 wt% resulted in substantial improvement up to 65 and 50% in proof stress and tensile strength, respectively, as compared to pearlitic CGI. However, adding up Si content to such a high level remarkably deteriorated elongation to failure. For each Si level, results showed that the Young’s modulus and tensile strength are fairly independent of the plate thickness (30–75 mm), however, a significant increase was observed for thin section plates, particularly 7 mm plate due to the higher nodularity in these sections.

  • 43.
    Ghasemi, Rohollah
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Scratch behaviour of silicon solid solution strengthened ferritic compacted graphite iron (CGI)2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, p. 318-325Article in journal (Refereed)
    Abstract [en]

    The present study focuses on scratch behaviour of a conventional pearlitic and a number of solid solution strengthened ferritic Compacted Graphite Iron (CGI) alloys. This was done by employing a single-pass microscratch test using a sphero-conical diamond indenter under different constant normal load conditions. Matrix solution hardening was made by alloying with different contents of Si; (3.66, 4.09 and 4.59 wt%. Si) which are named as low-Si, medium-Si and high-Si ferritic CGI alloys, respectively. A good correlation between the tensile and scratch test results was observed explaining the influence of CGI’s matrix characteristics on scratch behaviour both for pearlitic and fully ferritic solution strengthened ones. Both the scratch depth and scratch width showed strong tendency to increase with increasing the normal load, however the pearlitic one showed more profound deformation compared to the solution strengthened CGI alloys. Among the investigated alloys, the maximum and minimum scratch resistance were observed for high-Si ferritic CGI and pearlitic alloys, respectively. It was confirmed by the scratched surfaces analysed using Scanning Electron Microscopy (SEM) as well. In addition, the indenter’s depth of penetration value (scratch depth) was found as a suitable measure to ascertain the scratch resistance of CGI alloys. 

  • 44.
    Ghasemi, Rohollah
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Olofsson, Jakob
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E. W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Svensson, Ingvar L.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Modelling and simulation of local mechanical properties of high silicon solution-strengthened ferritic CGI materialsManuscript (preprint) (Other academic)
  • 45.
    Ghasemi, Rohollah
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Olofsson, Jakob
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E. W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Svensson, Ingvar L.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Modelling and simulation of local mechanical properties of high silicon solution-strengthened ferritic compacted graphite iron2017In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 30, no 3, p. 125-132Article in journal (Refereed)
    Abstract [en]

    This study focuses on the modelling and simulation of local mechanical properties of compacted graphite iron cast at different section thicknesses and three different levels of silicon, ranging from about 3.6% up to 4.6%. The relationship between tensile properties and microstructure is investigated using microstructural analysis and statistical evaluation. Models are generated using response surface methodology, which reveal that silicon level and nodularity mainly affect tensile strength and 0.2% offset yield strength, while Young′s modulus is primarily affected by nodularity. Increase in Si content improves both the yield and tensile strength, while reduces elongation to failure. Furthermore, mechanical properties enhance substantially in thinner section due to the high nodularity. The obtained models have been implemented into a casting process simulation, which enables prediction of local mechanical properties of castings with complex geometries. Very good agreement is observed between the measured and predicted microstructures and mechanical properties, particularly for thinner sections.

  • 46.
    Ghassemali, E.
    et al.
    School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
    Jarfors, A. E. W.
    School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
    Tan, M. -J
    School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
    Lim, S. C. V.
    Singapore Institute of Manufacturing Technology (SIMTech).
    Chew, M.
    Singapore Institute of Manufacturing Technology (SIMTech).
    Investigation of microstructure and hardness in microfoming of pure copper pins2010In: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 447-448, p. 381-385Article in journal (Refereed)
    Abstract [en]

    Microforming is defined as the process of production of metallic micro-parts with sub-millimeter dimension. There is as strong interaction between the scale of the microstructure and the size of the part affecting material flow, the so-called "size effect" in microforming processes. Conventional forming rules cannot be directly applied to the micro-scale forming. To better understand the implications for part geometry and properties, further investigation of the material flow related events is necessary. The aim of this work is to investigate microstructural evolution of pure copper during a micro-extrusion process - for production of micro-pins with diameters varying from 300 to 800Όm - by means of optical microscope (OM). Qualitative strain gradient distribution could be observed by those pictures. The results showed that change of micro-pins diameter and die angle affect the microstructure and strain distribution of the final product remarkably, that affect the mechanical properties of the pin formed. Furthermore, microhardness results were consistent with the microstructural observations. © (2010) Trans Tech Publications.

  • 47.
    Ghassemali, Ehsan
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Hernando, Juan Carlos
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Stefanescu, Doru M.
    The Ohio State University, Columbus, OH, United States.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Dluhoš, Jiří
    TESCAN Brno, Brno, Czech Republic.
    Petrenec, Martin
    TESCAN Brno, Brno, Czech Republic.
    Revisiting the graphite nodule in ductile iron2019In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 161, p. 66-69Article in journal (Refereed)
    Abstract [en]

    The growth mechanism of graphite nodules in ductile iron was experimentally investigated using high-resolution 3D tomography of an individual graphite nodule in a near-eutectic ductile iron. The dual beam scanning electron microscopy (FIB-SEM) technique was used for this purpose. Iron particles elongated in the radial direction were observed inside a graphite nodule. Some micro-voids were detected inside the nodule, mostly located at the end of the iron particles. These observations were compared with established theories about the growth of graphite nodules and iron entrapment/engulfment in between the graphite sectors during solidification of ductile iron. 

  • 48.
    Ghassemali, Ehsan
    et al.
    School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore.
    Jarfors, A. E. W.
    Jönköping University, School of Engineering, JTH, Mechanical Engineering. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Tan, Ming-Jen
    School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore.
    Lim, Samuel Chao Voo
    Singapore Institute of Manufacturing Technology (SIMTech).
    On the microstructure of micro-pins manufactured by a novel progressive microforming process2013In: International Journal of Material Forming, ISSN 1960-6206, E-ISSN 1960-6214, Vol. 6, no 1, p. 65-74Article in journal (Refereed)
    Abstract [en]

    Microforming is defined as the process of production of metallic micro-parts with at least two dimensions in sub-millimeter range. Many of these microforming processes have been investigated in laboratory-scale, which is not suitable for industrial applications. In this work, the feasibility of producing copper micro-pins using a novel progressive microforming process is demonstrated. This process has a good potential for mass production of micro-parts. The material flow behavior and the microstructure of the formed micro-pins were investigated by means of optical microscopy and simulation. From this study of material flow behavior with respect to different process conditions (die diameter, die design and punch diameters used), it will be shown how the respective material flow behavior in the progressive forming process influenced the microstructure evolution in the formed micro-pin. It was found in the experimental results that there is a soft zone on the micro-pins surface under specific process conditions. The microhardness results were consistent with the microstructural observations. Simulation was employed to understand the material flow direction under the punch during the microforming process and evaluate the position of the neutral zone in the disk-shape head of the micro-pin produced. This understanding of the neutral zone position with relation to the metal dead-zone as well as the material flow behavior was necessary to explain the dead-zone leakage in the microstructure and the occurrence of the soft zone. By decreasing the punch to die diameter ratio, and also choosing a die without entrance fillet radius, it was shown that the soft zones at the pin surface could be either minimized or entirely removed.

  • 49.
    Ghassemali, Ehsan
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting. Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting. Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing. Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    On the Formation of Micro-Shrinkage Porosities in Ductile Iron Cast Components2018In: Metals, E-ISSN 2075-4701, Vol. 8, no 7, article id 551Article in journal (Refereed)
    Abstract [en]

    A combination of direct austempering after solidification (DAAS) treatment and electron backscatter diffraction (EBSD) method was used to study the formation of micro-shrinkage porosities in ductile iron. Analyzing the aus-ferritic microstructure revealed that most of micro-shrinkage porosities are formed at the retained austenite grain boundaries. There was no obvious correlation between the ferrite grains or graphite nodules and micro-shrinkage porosities. Due to the absolute pressure change at the (purely) shrinkage porosities, the dendrite fragmentation rate during the DAAS process would be altered locally, which caused a relatively finer parent-austenite grain structure near such porosities.

  • 50.
    Ghassemali, Ehsan
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Tan, Ming-Jen
    School of Mechanical & Aerospace Engineering, Nanyang Technological University.
    Chua, Beng Wah
    Singapore Institute of Manufacturing Technology (SIMTech).
    Microstructure versus substructure size effect2016In: AIP Conference Proceedings / [ed] Francisco Chinesta, Elias Cueto and Emmanuelle Abisset-Chavanne, American Institute of Physics (AIP), 2016, Vol. 1769, p. 1-6, article id 090001Conference paper (Refereed)
    Abstract [en]

    In metal deformation, size effect is generally attributed to the interactive effect of grain size and specimen dimension. This work shows, however, that relative substructure dimensions should also be considered. Micro-compression tests on the micro-pins having different grain sizes revealed no significant size effect with respect to the mechanical behavior, even if the number of grains over the diameter of the micro-pins falls below its critical value. To justify the reason laying under this fact, a recovery annealing cycle was applied on the micro-pins to change the substructure properties without altering the mean grain size. A surprising drop in the flow stress of the recovery-annealed micro-pins implied the importance of considering subgrain size rather than grain size over the diameter of component for the size effect investigation.

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