Change search
Refine search result
1 - 33 of 33
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    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.
    Liljenfors, Tomas
    Assessment of Quality when Delivering Molten Aluminium Alloys Instead of Ingots2013In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 765, p. 266-270Article in journal (Refereed)
    Abstract [en]

    Recycled aluminium alloys manufactured at Stena Aluminium, in Älmhult, Sweden, are delivered in special designed transport containers, called thermoses. Thermoses are best described as an insulating layer protected by a steel cover with a heat loss of about 5 degrees/h. Three thermoses are transported by a truck, giving the possibility for a total capacity of about 24 tonnes delivered aluminium just-in-time to the foundry. By delivering a full load of liquid aluminium, about 2 tonnes of carbon dioxide emissions are saved, compared with delivering ingots. The aim of the paper is to assess the quality benefits, in terms of inclusions sedimentation and mechanical properties, assured by delivering aluminiummelts instead of ingots. The results indicate that materials produced by just-in-time melt delivery have slightly improved quality compared to ingots. The trends are explained in terms of quality, density and bifilm indexes, based on microstructural observations as well as tensile test data analysis.

  • 2.
    Cao, Haiping
    Jönköping University, School of Engineering, JTH, Mechanical Engineering. Jönköping University, School of Engineering, JTH. Research area Component Technology.
    On some characteristics of microstructure and defects in die-cast magnesium components2005In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 488-489, p. 283-286Article in journal (Refereed)
    Abstract [en]

    A mapping of fatigue crack growth rates in thick plates of a high strength aluminium alloy has been done. The plate thicknesses investigated was 100, 150 and 200 mm. In this work, material from near edge at near surface and mid-thickness has been investigated.

    Measurements of crack length has been performed using DC potential drop. Cyclic condensation is used in order to reveal crack growth behaviour for stage I and the earlier part of stage II crack growth.

    Influence of crack closure, crack branching and slow growing side cracks on fatigue crack growth rate of S-L and L-T oriented specimens are discussed. Variation of difference in growth rate in the upper part of the stage II growth between near surface and mid thickness positioned L-T specimens are found to vary with plate thickness.

  • 3.
    Cao, Haiping
    et al.
    Jönköping University, School of Engineering, JTH, Mechanical Engineering. Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting.
    Wessén, Magnus
    Jönköping University, School of Engineering, JTH, Mechanical Engineering. Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting.
    Mechanisms of segregation band defect formation in pressure die-cast magnesium components2005In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 488-489, p. 381-384Article in journal (Refereed)
    Abstract [en]

    Initially, when implementing a design automation system the focus is on successfully developing a system that generates design variants based on different customer specifications, i.e. the execution of system embedded knowledge and system output. However, in the long run two important aspects are the modelling and management of the knowledge that govern the designs. The increasing emphasis to deploy a holistic view on the products properties and functions implies an increasing number of life-cycle requirements. These requirements should all be used to enhance the knowledge-base allowing for correct decisions to be made. In a system for automated variant design these life-cycle requirements have to be expressed as algorithms and/or computational statements to be intertwined with the design calculations. The number of requirements can be significantly large and they are scattered over different systems. The aim of the presented work is to provide an approach for modelling of manufacturing requirements, supporting both knowledge execution and information management, in systems for automated variant design.

  • 4.
    Ceschini, Lorella
    et al.
    Bologna University.
    Jarfors, Anders
    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.
    Morri, Alessandro
    Bologna University.
    Rotundo, Fabio
    Bologna University.
    Toschi, Stefania
    Bologna University.
    Influence of SDAS on the high temperature tensile behavior of the C355 Al alloy2014In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 783-786, p. 228-233Article in journal (Refereed)
  • 5.
    Diószegi, Attila
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting. Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Fourlakidis, Vasilios
    Swerea - Swecast.
    Svensson, Ingvar L
    Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting. Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Fracture Mechanics of Gray Cast Iron2010In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 649, p. 517-522Article in journal (Refereed)
    Abstract [en]

    The fracture mechanism of gray cast iron was investigated on tension loaded samples produced under different conditions. The parameters studied included the graphite morphology, the carbon content, the inoculation and the cooling condition. The observations made reveal the role of the microstructure on crack propagation. The cracks were found to always propagate parallel with the graphite flakes. The interaction between the metallic matrix precipitated as primary austenite and graphite has been interpreted by a simplified model of the austenite reinforced eutectic cell. The geometrical transcription gave a standard crack component configuration with known mathematical solution. The microstructure observed in the experiments has been analysed by means of a novel interpretation. The fictitious stress intensity at yield and the fictitious maximum stress intensity at failure are strongly related to the relative shape of the eutectic cell and the fraction primary austenite. A different slope is observed for the material cooled at high rate when the precipitation of primary carbide reduces the stress intensity. The observed relations indicate that the tensile strength of the grey cast iron is the result of the collaboration between the toughness of the metallic matrix precipitated as primary austenite and the brittleness of the graphite phase. The shape and distribution of the primary austenite and graphite can be influenced by chemical composition, by inoculation or by the cooling condition, but they will maintain equilibrium with respect to the stress intensity.

  • 6.
    Diószegi, Attila
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Lora, Ruben
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Fourlakidis, Vasilios
    Swerea Swecast.
    Dynamic Coarsening of Austenite Dendrite in Lamellar Cast Iron Part 1 – Investigation based on interrupted solidification2014In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 790-791, p. 205-210Article in journal (Refereed)
    Abstract [en]

    Dynamic coarsening of austenite dendrite in lamellar cast iron has been studied for a hypoeutectic alloy. The common morphological parameter to characterize dynamic coarsening, secondary dendrite arm space has been replaced by the Modulus of primary dendrite (MPD) and the Hydraulic diameter of the interdendritic space (DHydIP) to interpret the dynamic coarsening with respect to the local solidification time. The obtained results demonstrate the coarsening process of both the solid and liquid phase. The interdendritic space is increasing as the contact time between the solid and liquid phase increases. The ratio between the DHydIP/MPD is strongly dependent on the precipitated fraction primary austenite indicating clearly the morphology variation during coarsening. The interrupted solidification method demonstrate that the observed coarsening process is not only a combination of the increasing fraction precipitated solid phase and the rearrangement of the solid - liquid interphase curvature but the volume change due to density variation is also contribute to the coarsening process.

  • 7.
    Domeij, Björn
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Solidification Chronology of the Metal Matrix and a Study of Conditions for Micropore Formation in Cast Irons Using EPMA and FTA2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 436-443Article in journal (Refereed)
    Abstract [en]

    Microsegregation is intimately coupled with solidification, the development of microstructure, and involved in the formation of various casting defects. This paper demonstrates how the local composition of the metal matrix of graphitic cast irons, measured using quantitative electron microprobe analysis, can be used to determine its solidification chronology. The method is applied in combination with Fourier thermal analysis to investigate the formation of micropores in cast irons with varying proportions of compacted and spheroidal graphite produced by remelting. The results indicate that micropores formed at mass fractions of solid between 0.77 and 0.91, which corresponded to a stage of solidification when the temperature decline of the castings was large and increasing. In 4 out of the 5 castings, pores appear to have formed soon after the rate of solidification and heat dissipation had reached their maximum and were decreasing. While the freezing point depression due to build-up of microsegregation and the transition from compacted to spheroidal type growth of the eutectic both influencing solidification kinetics and the temperature evolution of the casting, the results did not indicate a clear relation to the observed late deceleration of solidification.

  • 8.
    Elmquist, Lennart
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting. Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting. Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    On the Problems of a Migrating Hot Spot2010In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 649, p. 443-448Article in journal (Refereed)
  • 9.
    Elmquist, Lennart
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Soivio, Kaisu
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Cast iron solidification structure and how it is related to defect formation2014In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 790-791, p. 441-446Article in journal (Refereed)
  • 10.
    Fourlakidis, Vasilios
    et al.
    Swerea - Swecast.
    Diaconu, Lucian V
    University of Miskolc, Material science and engineering, dept. of Metallurgy and casting, Hungary.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting. Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Effects of Carbon Content on the Ultimate Tensile Strength in Gray Cast Iron2010In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 649, p. 511-516Article in journal (Refereed)
  • 11.
    Fourlakidis, Vasilios
    et al.
    Swerea SWECAST AB, Jönköping, Sweden.
    Diaconu, Lucian Vasile
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Strength prediction of lamellar graphite iron: From Griffith’s to hall-petch modified equation2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 272-279Article in journal (Refereed)
    Abstract [en]

    Traditionally, ultimate tensile strength (UTS) is used as the main property for the characterization of lamellar graphite iron (LGI) alloys under static loads. The main models found in the literature for predicting UTS of pearlitic lamellar graphite iron are based on either regression analysis on experimental data or on modified Griffith or Hall-Petch equation. In pearlitic lamellar graphite iron the primary austenite dendritic network, transformed to pearlite, reinforces the bulk material while the distance between those pearlite grains, defines the maximum continuous defect size in the bulk material. Recently the novel parameter of the Diameter of Interdendritic Space has been used to express the flow length in a modified Griffith equation for the prediction of the UTS in LGI. Nevertheless this model neglects the strengthening effect of the pearlite lamellar spacing within the perlite grains. A model based on modified Hall-Petch equation was developed in this work. The model considers the effect of both microstructure parameters and covers a broad spectrum of microstructure sizes typical for complex shape castings with various wall thicknesses. 

  • 12.
    Fourlakidis, Vasilios
    et al.
    Swerea Swecast.
    Lora, Ruben
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Dynamic Coarsening of Austenite Dendrite in Lamellar Cast Iron Part 2 – The influence of carbon composition2014In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 790-791, p. 211-216Article in journal (Refereed)
    Abstract [en]

    Investigation of dynamic coarsening in lamellar cast iron is extended over a wide interval ranging from hypoeutectic to eutectic composition. The dendrite morphology is defined on as-cast samples produced under various cooling rates. The as-cast morphology is considered being close to the one at the end of solidification. The obtained relations describing the coarsening process as a function of local solidification time and fraction austenite are compared to results obtained from interrupted solidification experiments. By using the Modulus of primary dendrite (MPD) and the Hydraulic diameter of the interdendritic space (DHyd IP) become possible to characterize the coarseness of a wide range of lamellar cast irons solidified under various cooling rates. 

  • 13.
    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%.

  • 14.
    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. 

  • 15.
    Hellström, Kristina
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Svidró, Péter
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Diaconu, Lucian Vasile
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Density variations during solidification of grey cast Iron2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, p. 155-162Article in journal (Refereed)
    Abstract [en]

    As part of moving towards a sustainable production of diesel engines for heavy vehicle applications, the ability to predict casting defects has become ever so important. In order to model the solidification process for cast components correctly, it is of essence to know how the material will actually behave. To produce sound castings, often of complex geometry, the industry relies on various simulation software for the prediction and avoidance of defects. Thermophysical properties, such as density, play an important part in these simulations. Previous measurements of how the volume of liquid grey iron changes with temperature has been made with a conventional dilatometer. Measurements have also been made in the austenitic range, then on iron-carbon-silicon alloys with a carbon content lower than 1.5 wt%. Based on these measurements the density variations during solidification were calculated. The scope for this paper is to model the volume changes during solidification with the control volume finite difference method, using data from the density measurements. 

  • 16.
    Hernando, Juan Carlos
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    On the primary solidification of compacted graphite iron: Microstructure evolution during isothermal coarsening2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 90-97Article in journal (Refereed)
    Abstract [en]

    It is widely accepted that in most commercial hypoeutectic alloys, both static mechanicalproperties and feeding characteristics during solidification, are extremely linked to the coarseness ofthe primary phase. It is therefore of critical importance to provide tools to control and predict thecoarsening process of the dendritic phase present in hypoeutectic melts. The characterization of theprimary phase, a product of the primary solidification, has traditionally been neglected whencompared to the eutectic solidification characterization in cast iron investigations. This workpresents the morphological evolution of the primary austenite present in a hypoeutectic compactedgraphite cast iron (CGI) under isothermal conditions. To that purpose, a base spheroidal graphitecast iron (SGI) material with high Mg content is re-melted in a controlled atmosphere and reversedinto a CGI melt by controlling the Mg fading. An experimental isothermal profile is applied to thesolidification process of the experimental alloy to promote an isothermal coarsening process of theprimary austenite dendrite network during solid and liquid coexistence. Through interruptedsolidification experiments, the primary austenite is preserved and observed at room temperature. Byapplication of stereological relations, the primary phase and its isothermal coarsening process arecharacterized as a function of the coarsening time applied. The microstructural evolution observedin the primary austenite in CGI and the measured morphological parameters show a similar trend tothat observed for lamellar graphite cast iron (LGI) in previous investigations. The modulus of theprimary austenite, Mγ, and the nearest distance between the centre of gravity of neighbouringaustenite particles, Dγ, followed a linear relation with the cube root of coarsening time.

  • 17.
    Jarfors, A. E. W.
    Singapore Inst. of Mfg. Technology, Process Technology Division, Precision Metal Forming Group, Singapore.
    A Discussion of the Dynamic Specific Heat during Solidification2003In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 437-438, p. 391-394Article in journal (Other academic)
    Abstract [en]

    State-of-the-art solidification theory shows that the apparent latent heat of fusion decreases with increasing cooling rates, due to the creation of lattice defects. A portion of the defects condenses during and after solidification, releasing heat, causing the apparent specific heat to be dynamic. Experimental data on copper shows an increase and a maximum in the apparent specific heat at moderate cooling rates. An extension of the existing theory for dynamic specific heats is made. Previous models do not reproduce the maximum, nor do they reproduce the equilibrium value at low cooling rates. The presently derived model reproduces all essential features of the experimentally data. It also clearly shows that the effect at moderate cooling rates is significant and the tabulated values are not applicable for modelling casting.

  • 18.
    Jarfors, A. E. W.
    et al.
    Singapore Inst. of Mfg. Technology, Process Technology Division, Precision Metal Forming Group, Singapore.
    Sim, G. C.
    Singapore Inst. of Mfg. Technology, Process Technology Division, Precision Metal Forming Group, Singapore.
    San, T. E.
    Singapore Inst. of Mfg. Technology, Process Technology Division, Precision Metal Forming Group, Singapore.
    Influence of Process Parameters on Reaction Products during Self-Propagating High-Temperature Synthesis of Porous NiTi2003In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 437-438, p. 475-478Article in journal (Refereed)
    Abstract [en]

    NiTi is proposed to be a biomaterial suitable for bone replacements. Reactive synthesis, Self-Propagating High-Temperature Synthesis (SHS) of NiTi from Ni and Ti powder is a suitable method to produce porous structures to promote osseointegration. The influence of pressed density and ignition temperature on the reaction products formed is investigated. Porosity after pressing was 20%, 30% and 40 % and ignition temperatures were 400°C, 500°C and 600°C. The reaction products found were NiTi, as well as Ti2Ni and Ni3Ti, in addition to residual Ni and Ti. The amount of NiTi formed increases with ignition temperature, with a maximum at an initial porosity of 30% and ignition temperature of 600°C. This coincides with the minimum amount of residual Ni and Ti. The reaction imbalance is caused by the formation of Ti2Ni at high pressed densities and by a preferential nucleation of Ni3Ti, both suggested to be dominated by the effective contact area between the Ni and Ti particles after pressing.

  • 19.
    Kasvayee, Keivan Amiri
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Ciavatta, Matteo
    University of Bologna, Bologna, Italy.
    Ghassemali, Ehsan
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Svensson, Ingvar L.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Effect of Boron and Cross-Section Thickness on Microstructure and Mechanical Properties of Ductile Iron2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 249-256Article in journal (Refereed)
    Abstract [en]

    Eeffect of Boron addition on the microstructure and mechanical properties of ductile iron, GJS-500-7 grade was studied. Three cast batches with the Boron content of 10, 49 and 131ppm were cast in a casting geometry containing plates with thicknesses of 7, 15, 30, 50 and 75mm. Microstructure analysis, tensile test, and hardness test were performed on the samples which were machined from the casting plates. Addition of 49 ppm Boron decreased pearlite fraction by an average of 34±6% in all the cast plates. However, minor changes were observed in the pearlite fraction by increasing Boron from 49 to 131 ppm. Variation in the plate thickness did not affect the pearlite fraction. The 0.2% offset yield and ultimate tensile strength was decreased by an average of 11±1% and 18±2%, respectively. Addition of 49 ppm Boron decreased Brinell hardness by 16±1%, while 11±2% reduction was obtained by addition of 131ppm Boron.

  • 20.
    Pang, J. J.
    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.
    Singapore Institute of Manufacturing Technology.
    Chuang, P. D.
    Miracle Machines Pte. Ltd., Singapore.
    Glass formation and structural study of Ti50Cu50 alloy by molecular dynamics2010In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 638-642, p. 1665-1670Article in journal (Refereed)
    Abstract [en]

    Ti-based metallic glasses (MGs) due to their relative low densities exhibit ultrahigh specific characteristics. In this article the glass-forming behavior and atomic structure of Ti50Cu50 MG were investigated through molecular dynamics simulation (MDS) using the general embedded-atom method (GEAM) potential. As observed experimentally, simulated Ti 50Cu50 alloy undergoes three states on quenching: (i) equilibrium liquid; (ii) supercooled liquid and (iii) glassy solid. The atomic configuration of the glass was analysed based on the radial distribution function (RDF) and Voronoi tessellation (VT). It was found that there exist a variety of polyhedral units in Ti50Cu50 MG, where distorted icosohedral and bcc clusters are dominant. © (2010) Trans Tech Publications.

  • 21.
    Salomonsson, Kent
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jarfors, Anders E.W.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Three-dimensional microstructural characterization of cast iron alloys for numerical analyses2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 427-435Article in journal (Refereed)
    Abstract [en]

    In this paper, we aim at characterizing three different cast iron alloys and their microstructural features, namely lamellar, compacted and nodular graphite iron. The characterization of microscopic features is essential for the development of methods to optimize the behavior of cast iron alloys; e.g. maximize thermal dissipation and/or maximize ductility while maintaining strength. The variation of these properties is commonly analyzed by metallography on two-dimensional representations of the alloy. However, more precise estimates of the morphologies and material characteristics are obtained by three-dimensional reconstruction of microstructures. The use of X-ray microtomography provides an excellent tool to generate high resolution threedimensional microstructure images. The characteristics of the graphite constituent in the microstructure, including the size, shape and connectivity, were analyzed for the different cast iron alloys. It was observed that the lamellar and compacted graphite iron alloys have relatively large connected graphite morphologies, as opposed to ductile iron where the graphite is present as nodules. The results of the characterization for the different alloys were ultimately used to generate finite element models.

  • 22.
    Selin, Martin
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting.
    Holmgren, Daniel
    Svensson, Ingvar L.
    Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting.
    Effect of Alloying Elements on Graphite Morphology in CGI2010In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Solidification and Gravity V, Vol. 649, p. 171-176Article in journal (Refereed)
    Abstract [en]

    Understanding how alloying elements and amounts affect the shape and size of graphite in compacted graphite cast irons could be of great importance. Some important material properties that are affected by the graphite shape are tensile strength and thermal conductivity. Knowing the effect of alloying additions could be of assistance when trying to optimise material for a specific application. In order to determine how graphite changes depending on alloying additions the microstructure of nineteen CGI materials were investigated. All melts were based on one chemical composition and alloying elements were added to obtain melts with variation in magnesium, silicon, copper, tin, chromium and molybdenum. Some of the more important microstructure features that were analysed are the amount and size of different graphite particles. The result from this analysis should give an indication on what features each alloying element affect and how these features varies with alloying amount.

  • 23.
    Sjölander, Emma
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting. Scania AB.
    Seifeddine, Salem
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Fracasso, Fredrico
    University of Padova.
    Influence of Quench Rate on the Artificial Ageing Response of an Al-8Si-0.4Mg Cast Alloy2015In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 828-829, p. 219-225Article in journal (Refereed)
    Abstract [en]

    The aim of the study is to present the influence of quench rate on the artificial ageing response of Al-8%Si-0.4%Mg cast alloy in terms of Brinell hardness and yield strength. The investigated material was produced by a gradient solidification technique and exhibited a microstructure that corresponds to the one of gravity die castings, with a dendrite arm spacing of approximately 25 μm. The study comprises two solution treatment temperatures, five quench rates and artificial ageingtimes exceeding 100 hours at 170 and 220 ⁰C. The microstructure and concentration profiles of Mgand Si were evaluated using energy and wavelength dispersive spectroscopy. Microstructural examination reveals an increment of solutes in the Al-matrix when higher solution treatment temperatures accompanied with high quench rates are applied and shows how both Si and Mgatoms have diffused towards the eutectic during quenching. Consequently, i.e. by increasing the levels of solutes and vacancies, the highest strength levels were realized. The study confirmed that quench rates above 2 ⁰C /s do not offer substantial strength improvement while quenching at lower rates resulted in a lower peak hardness and longer times to peak.

  • 24.
    Skoglund, Peter
    et al.
    Scania CV AB, Södertälje, Sweden.
    Elfsberg, Jessica
    Scania CV AB, Södertälje, Sweden.
    Ipek, Nulifer
    Scania CV AB, Södertälje, Sweden.
    Diaconu, Lucian Vasile
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Larsson, Mari
    Volvo Group Trucks Operations, Skövde, Sweden.
    Schmidt, Pål
    Volvo Group Trucks Technology, Gropegårdsgatan, Göteborg, Sweden.
    Thermo-mechanical fatigue of grey cast iron for cylinder heads - Effect of niobium, molybdenum and solidification time2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 377-384Article in journal (Refereed)
    Abstract [en]

    Grey iron alloyed with molybdenum and niobium in seven different compositions has been casted using three, in industrial components viable, solidification times which resulted in 21 different samples. The samples have been investigated with respect to microstructure, static properties and thermo-mechanical fatigue performance. It was found that the solidification time is very important for both the static and thermo-mechanical performance. If the solidification time is long the properties are controlled entirely by the large graphite flakes and there is no influence of the alloying elements. On the other hand if the solidification time can be kept short the need for alloying elements may be removed. For the shorter solidification times an influence from the matrix and thus the alloying elements can be seen. It was found that molybdenum enhances TMF-life while no such effect was found for niobium. Niobium, on the other hand, has a larger effect on static strength than molybdenum and also on the cyclic stress in the thermo-mechanical fatigue experiments. 

  • 25. Su, C. W.
    et al.
    Oon, P. H.
    Bai, Y. H.
    Jarfors, A. E. W.
    Mechanical properties and microstructure of aluminum alloy Al-6061 obtained by the liquid forging process2010In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 654-656, p. 1420-1423Article in journal (Refereed)
    Abstract [en]

    The liquid forging process has the flexibilities of casting in forming intricate profiles and features while imparting the liquid forged components with superior mechanical strength compared to similar components obtained via casting. Additionally, liquid forging requires significantly lower machine loads compared to solid forming processes. Currently, components that are formed by liquid forging are usually casting alloys of aluminum. This paper investigates the suitability of liquid forging a wrought aluminum alloy Al-6061 and the mechanical properties after forming. The proper handling of the Al-6061 alloy in its molten state is important in minimizing oxidation of its alloying elements. By maintaining the correct alloying composition of Al-6061 after liquid forging, these Al-6061 samples can subsequently undergo a suitable heat treatment process to significantly improve their yield strengths. Results show that the yield strengths of these liquid forged Al-6061 samples can be increased from about 90MPa, when they are in the as-liquid forged state, to about 275MPa after heat treatment. This improved yield strength is comparable to that of Al-6061 samples obtained by solid forming processes. As such, the liquid forging process here has been shown to be capable of forming wrought aluminum alloy components that has the potential for structural applications. © (2010) Trans Tech Publications.

  • 26.
    Svensson, Ingvar L.
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Salomonsson, Kent
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Mathematical characterization of the tensile deformation curve of cast iron materials2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 444-450Article in journal (Refereed)
    Abstract [en]

    The manufacturing process gives cast iron castings properties which are dependent on component design, metallurgy and casting method. Factors such as local wall thickness influences the coarseness and type of microstructure and the castings will have local properties depending on the local metallurgical and thermal history. The stress/strain behaviour of cast materials is typically determined by performing a tensile test in a tensile test machine. The deformation behaviour will normally be determined by two mechanisms, namely, elastic and plastic phenomena. The plastic behaviour is based on dislocation movements in the lattice. Commonly, the deformation history of cast iron involves elastic, plastic and crack phases. The cast iron material has a complex microstructure and first order equations cannot be used to predict the deformation during loading. Until methods have been developed, the characterization of complex microstructure materials such as cast iron has to be determined by use of empirical methods. The empirical methods have to couple the internal microstructure and composition of the material with deformation phenomena during loading. The paper will show a method to characterize tensile test curves of cast iron materials which can be used to couple deformation phenomena with for example microstructure. The equations are aimed to make the tensile test curve ready for curve fitting and optimization in two steps. Each stress/strain curve is like a finger print of the material and requires well performed tests and some advices are given. The paper also wants to encourage researchers and people working with tensile testing to get out more of their effort to measure strength of cast iron materials and connect the result to the microstructure of the specimens. 

  • 27.
    Svidró, Péter
    et al.
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Jönsson, Pär G.
    Department of Material Science and Technology, School of Industrial Engineering and Management, KTH Royal Institute of Technology, Sweden.
    Extended method of volume change measurements during solidification of lamellar graphite iron2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 163-170Article in journal (Refereed)
    Abstract [en]

    Lamellar graphite iron (LGI) is an important technical alloy used to produce cast components for the automotive and the marine industry. The performance of the component is defined by the solidification sequence. Therefore, a lot of research work has been done in the field of solidification. The present work introduces a new measurement approach that combines advanced dilatation measurements with thermal analysis to investigate the solidification of LGI. The method involves a thermally balanced spherical sample. The temperature values are measured in the geometrical center and on the surface of the sample. The released heat of solidification is calculated by using the Fourier Thermal Analysis (FTA) method. The displacement values are measured on the surface of the sample. The volume change is calculated from the displacement data. The dilatation results clearly shows the advantage of the multidirectional measurement. 

  • 28.
    Thomser, Corinna
    et al.
    MAGMA Gießereitechnologie GmbH Aachen, Germany.
    Olofsson, Jakob
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Gurevitch, Vitalii
    MAGMA Gießereitechnologie GmbH Aachen, Germany.
    Influence of local microstructure on stresses, durability and fracture mechanics of cast iron components2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 925, p. 264-271Article in journal (Refereed)
    Abstract [en]

    Cast iron components show a large variety of different microstructures in dependence on chemical composition, inoculation and cooling conditions. In conventional static and dynamic calculations as well as in fracture mechanics assessment of cast iron components, the influence of local microstructure on the overall behavior of the component is not considered. Usually one material dataset is applied for the whole material. The paper describes recent developments in the field of the prediction of local microstructure and its correlation to local stress-strain, fatigue durability as well as fracture toughness. The benefit of combining casting process simulation with lifetime predictions and fracture mechanics assessment is shown for selected examples. By integrating casting process simulation, microstructure modelling, local material characterization and load analysis, a simulation based approach for predicting the behavior and performance of cast iron components already during the design stage is enabled. Thus, the local assessment helps designers to assess risks and strive for light weight designs before the casting is made.

  • 29.
    Vazehrad, Sadaf
    et al.
    KTH.
    Elfsberg, Jessica
    Scania CV AB.
    Diószegi, Attila
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    On Factors Influencing Macro Shrinkage Porosity Formation in Compacted Graphite Iron2014In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 790-791, p. 429-434Article in journal (Refereed)
    Abstract [en]

    The purpose of this work is to investigate the relation between macro shrinkage porosity level and the level of graphite nodularity, gaseous elements and the size of eutectic colonies in compacted graphite iron. Also, the internal shrinkage-pore surfaces were analyzed by SEM and EDS techniques. It was found that samples with higher shrinkage porosity level, contained higher level of graphite nodularity and number of eutectic colonies. Also, samples with higher level of gaseous elements (Hydrogen and Nitrogen) showed higher tendency to shrinkage porosity formation. Austenite dendrites with different morphologies were observed inside the pores, indicating that were formed at different times during solidification, and the surface of the pores were covered with a layer of carbon film indicating that the pores were internal, with no contact to the atmosphere at elevated temperatures.

  • 30.
    Verezub, Olga
    et al.
    University of Miskolc, Hungary.
    Kaptay, George
    University of Miskolc, Hungary.
    Matsushita, Taishi
    Royal Institute of Technology, Sweden.
    Mukai, Kusuhiro
    Kyushu Institute of Technology, Japan.
    Penetration dynamics of solid particles into liquids high-speed experimental results and modelling2005In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 473-474, p. 429-434Article in journal (Refereed)
    Abstract [en]

    Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

  • 31.
    Wang, Yongsheng
    et al.
    School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
    Tan, Ming Jen
    School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
    Jarfors, Anders E. W.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Corrosion Behavior and Surface Analysis of Melt-spun Mg-based Metallic Glass in Physiological Saline Solution2012In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 706-709, p. 606-611Article in journal (Refereed)
    Abstract [en]

    The developed Mg-based metallic glass shows great potential as implants in biomedicalapplications instead of crystalline Mg alloys, which may possesses acceptable corrosion properties. Inthis study, corrosion behaviors of melt-spun amorphous Mg67Zn28Ca5 ribbons were investigated inphysiological saline solution. Electrochemical testing and hydrogen evolution rate indicated that theglassy ribbons obtained at lower wheel speed were more noble with smaller corrosion current, andpossessed a comparatively lower corrosion rate in physiological saline solution. Surface morphologyanalysis revealed that glassy Mg67Zn28Ca5 ribbons exhibited a strong susceptibility to localizedpitting corrosion. A Zn-rich passive layer was formed on the surfaces of the glassy ribbons, indicatingthat Zn was an effective alloying element to enhance the corrosion resistance of amorphousMg67Zn28Ca5 alloys.

  • 32.
    Wassén, Magnus
    et al.
    Jönköping University, School of Engineering, JTH, Mechanical Engineering. Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting.
    Cao, Haiping
    Jönköping University, School of Engineering, JTH, Mechanical Engineering. Jönköping University, School of Engineering, JTH. Research area Materials and Manufacturing - Casting.
    The Effect of Mould Constraints on the 0.2% Proof Stress of As-Cast Mg-Al Alloys2005In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 488-489, p. 165-168Article in journal (Refereed)
    Abstract [en]

    A mapping of fatigue crack growth rates in thick plates of a high strength aluminium alloy has been done. The plate thicknesses investigated was 100, 150 and 200 mm. In this work, material from near edge at near surface and mid-thickness has been investigated. Measurements of crack length has been performed using DC potential drop. Cyclic condensation is used in order to reveal crack growth behaviour for stage I and the earlier part of stage II crack growth. Influence of crack closure, crack branching and slow growing side cracks on fatigue crack growth rate of S-L and L-T oriented specimens are discussed. Variation of difference in growth rate in the upper part of the stage II growth between near surface and mid thickness positioned L-T specimens are found to vary with plate thickness.

  • 33. Zsolt, T-P
    et al.
    Zhang, Yafan
    Belov, Ilja
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing - Surface technology.
    Nee, Hans-Peter
    Bakowski, Mietek
    Investigation of Pressure Dependent Thermal Contact Resistance between Silver Metallized SiC Chip and DBC Substrate2015In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 821-823, p. 452-455Article in journal (Refereed)
1 - 33 of 33
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf