Change search
Link to record
Permanent link

Direct link
Publications (10 of 87) Show all publications
Bogdanoff, T., Tiryakioglu, M., Jarfors, A. E. .. & Ghassemali, E. (2024). A simple procedure to assess the Complete Melt Quality in aluminium castings: implementation in a die-casting and a rheo-casting. International Journal of Cast Metals Research, 37(1), 71-79
Open this publication in new window or tab >>A simple procedure to assess the Complete Melt Quality in aluminium castings: implementation in a die-casting and a rheo-casting
2024 (English)In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 37, no 1, p. 71-79Article in journal (Refereed) Published
Abstract [en]

A new simple approach was developed to assess the Complete Melt Quality of aluminium cast alloys throughout the production line. The approach relies on the concurrent use of reduced pressure tests (RPT) and tensile tests at each station in the production line when the melt is transferred and/or processed. These tests can be used to determine the source of melt-related problems in the production line. Two case studies from the procedure of both an aluminium die-casting and a rheo-casting plant showed that melts were significantly damaged in the tower furnace and got progressively more damaged through the production line proven by the RPT, tensile test, and fracture surface analysis results.

Place, publisher, year, edition, pages
Taylor & Francis, 2024
Keywords
Melt transfers, bifilms, degassing, liquid metal damage, porosity
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-63218 (URN)10.1080/13640461.2023.2293415 (DOI)001125756600001 ()2-s2.0-85179712295 (Scopus ID);intsam;924887 (Local ID);intsam;924887 (Archive number);intsam;924887 (OAI)
Funder
VinnovaKnowledge Foundation
Available from: 2024-01-08 Created: 2024-01-08 Last updated: 2024-01-08Bibliographically approved
Mohammadi Zahrani, M., Ranjbarnodeh, E., Ketabchi, M. & Ghassemali, E. (2024). Microstructure evolution and mechanical properties of laser-welded joints of 1.2 GPa-class quenching and partitioning steel. Optics and Laser Technology, 170, Article ID 110257.
Open this publication in new window or tab >>Microstructure evolution and mechanical properties of laser-welded joints of 1.2 GPa-class quenching and partitioning steel
2024 (English)In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 170, article id 110257Article in journal (Refereed) Published
Abstract [en]

Laser welding of 1.2 GPa-class cold-rolled quenching and partitioning steel with martensite + retained austenite microstructure was performed at different heat inputs ranging from 91–240 J·mm−1 using a CO2 laser. Scanning electron microscopy, electron backscatter diffraction, and uniaxial tensile testing equipped with digital image correlation were employed to characterize the microstructural and mechanical evolution of the joints. The results revealed that the fusion zone and upper-critical HAZ comprised full martensite with high microhardness. The HAZ contained a narrow softened zone with a minimum width of ∼0.6 µm and at least 48 HV microhardness drop because of the martensite tempering. Martensite decomposition and precipitation of carbides were noticeable at higher heat inputs, so that the hardness of the softened zone was declined. At the welding heat input of 91 J·mm−1, the yield and tensile strengths were 841 and 1270 MPa, respectively, which represented reductions of 5.5 and 0.78% compared to the base material properties. The joint efficiency of 99.2% was achieved at the lowest heat input. The tensile deformation was primarily concentrated in the softened zone and was small in the fusion zone. However, the participation of the base material to tensile deformation was enhanced at lower heat inputs, leading to higher elongation values up to ∼11.9% during tensile testing.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
HAZ softening, Heat input, Laser welding, Mechanical property, Microstructure, Quenching and partitioning steel, Carbides, Carbon dioxide lasers, Cold rolling, Laser beam welding, Martensite, Metal cladding, Microhardness, Quenching, Scanning electron microscopy, Steel sheet, Tensile strength, Tensile testing, Base material, Fusion zones, Laser welded joints, Low heat inputs, Microstructure evolutions, Quenching and partitioning, Tensile deformation
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-62876 (URN)10.1016/j.optlastec.2023.110257 (DOI)001110256900001 ()2-s2.0-85175733355 (Scopus ID)
Available from: 2023-11-13 Created: 2023-11-13 Last updated: 2024-01-09Bibliographically approved
Bogdanoff, T., Ghassemali, E., Jarfors, A. E. .. & Seifeddine, S. (2024). The impact of HIP process and heat treatment on the mechanical behaviour of an Al–Si–Mg alloy component. International Journal of metalcasting
Open this publication in new window or tab >>The impact of HIP process and heat treatment on the mechanical behaviour of an Al–Si–Mg alloy component
2024 (English)In: International Journal of metalcasting, ISSN 1939-5981, E-ISSN 2163-3193Article in journal (Refereed) Epub ahead of print
Abstract [en]

This study investigates the effect of hot isostatic pressing (HIPping) on the static and fatigue properties of sand-casting A356 aluminium alloys. HIPping is a method to improve the fatigue properties in aluminium cast material by reducing or eliminating the inner porosities. Investigation of the complex interaction between the microstructural features on mechanical properties before and after the HIPping process was examined using computed tomography and scanning electron microscopy (SEM). Castings generally contain pores and defects that have a detrimental impact on the fatigue properties. The HIPping process closes the porosities in all investigated samples with an increase in density. Without significant defects, the mechanical performance improved in the finer microstructure. However, a considerable variation in the results was found between the different conditions, whereas the coarser microstructure with larger porosities before HIPping showed remarkably reduced results. The high-cycle fatigue-tested samples showed reduced fatigue propagation zone in the coarser microstructure. Moreover, large cleavage areas containing bifilms in the fracture surfaces indicate that the healing process of porosities is inefficient. These porosities are closed but not healed, resulting in a detrimental effect on the static and dynamic properties.

Place, publisher, year, edition, pages
Springer, 2024
Keywords
Al–Si alloys, castings, fatigue properties, heat treatment, hot isostatic pressing (HIP), Aluminum alloys, Computerized tomography, Defects, Fatigue testing, High-cycle fatigue, Magnesium alloys, Microstructure, Porosity, Scanning electron microscopy, Silicon alloys, Sintering, Al-Si alloy, Al-si-mg alloys, Alloy components, Coarse microstructure, Hot isostatic pressing, Hot-isostatic pressings, Mechanical behavior, Sand-castings, Static properties
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-63436 (URN)10.1007/s40962-023-01226-z (DOI)001141893800001 ()2-s2.0-85182182478 (Scopus ID)HOA;;933494 (Local ID)HOA;;933494 (Archive number)HOA;;933494 (OAI)
Available from: 2024-01-29 Created: 2024-01-29 Last updated: 2024-01-31
Ousiabou, B., Conway, P. L. J. & Ghassemali, E. (2023). A strategy for designing alloys with improved hydrogen embrittlement resistance. In: : . Paper presented at 17th European Congress and Exhibition on Advance Materials and Processes, FEMS EUROMAT 2023, 03-07 September 2023, Germany.
Open this publication in new window or tab >>A strategy for designing alloys with improved hydrogen embrittlement resistance
2023 (English)Conference paper, Oral presentation only (Refereed)
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-63232 (URN)
Conference
17th European Congress and Exhibition on Advance Materials and Processes, FEMS EUROMAT 2023, 03-07 September 2023, Germany
Available from: 2024-01-09 Created: 2024-01-09 Last updated: 2024-01-09Bibliographically approved
Conway, P. L. J. & Ghassemali, E. (2023). Development of high-performance cast Al-Si alloys through high-throughput screening and HEA concepts. In: : . Paper presented at 17th European Congress and Exhibition on Advance Materials and Processes, FEMS EUROMAT 2023, 03-07 September 2023, Germany.
Open this publication in new window or tab >>Development of high-performance cast Al-Si alloys through high-throughput screening and HEA concepts
2023 (English)Conference paper, Oral presentation only (Refereed)
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-63234 (URN)
Conference
17th European Congress and Exhibition on Advance Materials and Processes, FEMS EUROMAT 2023, 03-07 September 2023, Germany
Available from: 2024-01-09 Created: 2024-01-09 Last updated: 2024-01-09Bibliographically approved
Di Egidio, G., Martini, C., Börjesson, J., Ghassemali, E., Ceschini, L. & Morri, A. (2023). Dry sliding behavior of AlSi10Mg alloy produced by Laser-based Powder Bed Fusion: influence of heat treatment and microstructure. Wear, 516-517, Article ID 204602.
Open this publication in new window or tab >>Dry sliding behavior of AlSi10Mg alloy produced by Laser-based Powder Bed Fusion: influence of heat treatment and microstructure
Show others...
2023 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 516-517, article id 204602Article in journal (Refereed) Published
Abstract [en]

The L-PBF AlSi10Mg alloy is widely used in the production of structural parts in the transportation sector. However, the high stresses caused by the severe operating conditions require an optimal combination of mechanical and tribological properties. This paper reports on the effect of optimized T5 heat treatment (direct artificial aging: 4 h at 160 °C) and novel T6 heat treatment (rapid solution: 10 min at 510 °C, followed by artificial aging: 6 h at 160 °C) on the tribological behavior of the L-PBF AlSi10Mg alloy. Dry sliding tests (ball-on-disk) were carried out using AlSi10Mg samples as rotating disks against an Al2O3 stationary ball. The optimized T5 led to the formation of a stable protective oxide layer well adherent on the worn surface, increasing the wear resistance of the alloy. In addition, the novel T6 improved wear resistance compared to conventional T6 due to microstructural refinement induced by shorter solutionizing. The sub-surface analysis of the wear tracks highlighted the higher cohesion between the more homogeneous and finer Si particles and the α-Al matrix, as well as the improved load-bearing support compared to the coarser microstructure induced by conventional T6. Therefore, the new T6 could be the optimal solution for high-performance components.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
AlSi10Mg, Electron microscopy, Heat treatment, Laser-based powder Bed Fusion (L-PBF), Sliding wear
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-59382 (URN)10.1016/j.wear.2022.204602 (DOI)000921319100001 ()2-s2.0-85145696137 (Scopus ID);intsam;59382 (Local ID);intsam;59382 (Archive number);intsam;59382 (OAI)
Available from: 2023-01-16 Created: 2023-01-16 Last updated: 2023-03-02Bibliographically approved
Ousiabou, B., Conway, P. L. J. & Ghassemali, E. (2023). High-throughput CALPHAD for designing hydrogen-embrittlement resistant alloys. In: : . Paper presented at Materials Today Conference 2023, 2-5 August 2023, Singapore.
Open this publication in new window or tab >>High-throughput CALPHAD for designing hydrogen-embrittlement resistant alloys
2023 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-63244 (URN)
Conference
Materials Today Conference 2023, 2-5 August 2023, Singapore
Available from: 2024-01-09 Created: 2024-01-09 Last updated: 2024-01-09Bibliographically approved
Di Egidio, G., Martini, C., Börjesson, J., Ghassemali, E., Ceschini, L. & Morri, A. (2023). Influence of Microstructure on Fracture Mechanisms of the Heat-Treated AlSi10Mg Alloy Produced by Laser-Based Powder Bed Fusion. Materials, 16(5), Article ID 2006.
Open this publication in new window or tab >>Influence of Microstructure on Fracture Mechanisms of the Heat-Treated AlSi10Mg Alloy Produced by Laser-Based Powder Bed Fusion
Show others...
2023 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, no 5, article id 2006Article in journal (Refereed) Published
Abstract [en]

Few systematic studies on the correlation between alloy microstructure and mechanical failure of the AlSi10Mg alloy produced by laser-based powder bed fusion (L-PBF) are available in the literature. This work investigates the fracture mechanisms of the L-PBF AlSi10Mg alloy in as-built (AB) condition and after three different heat treatments (T5 (4 h at 160 °C), standard T6 (T6B) (1 h at 540 °C followed by 4 h at 160 °C), and rapid T6 (T6R) (10 min at 510 °C followed by 6 h at 160 °C)). In-situ tensile tests were conducted with scanning electron microscopy combined with electron backscattering diffraction. In all samples the crack nucleation was at defects. In AB and T5, the interconnected Si network fostered damage at low strain due to the formation of voids and the fragmentation of the Si phase. T6 heat treatment (T6B and T6R) formed a discrete globular Si morphology with less stress concentration, which delayed the void nucleation and growth in the Al matrix. The analysis empirically confirmed the higher ductility of the T6 microstructure than that of the AB and T5, highlighting the positive effects on the mechanical performance of the more homogeneous distribution of finer Si particles in T6R.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
Backscattering, Fracture, Heat treatment, Microstructure, Morphology, Nucleation, Silicon, Tensile strength, Tensile testing, Alloy microstructure, Condition, Electron backscattering, Fracture mechanisms, In-situ tensile test, Laser-based, Laser-based powder bed fusion, Mechanical failures, Powder bed, Systematic study, Scanning electron microscopy, AlSi10Mg, laser-based powder bed fusion (L-PBF)
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-60030 (URN)10.3390/ma16052006 (DOI)000948281900001 ()2-s2.0-85149850554 (Scopus ID)GOA;intsam;868742 (Local ID)GOA;intsam;868742 (Archive number)GOA;intsam;868742 (OAI)
Funder
European Commission, CN00000023
Available from: 2023-03-27 Created: 2023-03-27 Last updated: 2023-04-03Bibliographically approved
Bogdanoff, T., Tiryakioğlu, M., Jarfors, A. E. .., Seifeddine, S. & Ghassemali, E. (2023). On the combined effects of surface quality and pore size on the fatigue life of Al–7Si–3Cu–Mg alloy castings. Materials Science & Engineering: A, 885, Article ID 145618.
Open this publication in new window or tab >>On the combined effects of surface quality and pore size on the fatigue life of Al–7Si–3Cu–Mg alloy castings
Show others...
2023 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 885, article id 145618Article in journal (Refereed) Published
Abstract [en]

This study has aimed to determine the effects of surface quality and pore size, obtained by different levels of hydrogen content of the liquid metal, on the fatigue behavior of an Al–7%Si–3%Cu–Mg casting alloy. Three surface conditions have been studied: as-cast rough, as-cast smooth, and standard machined and polished surface. The S–N curves have shown that surface roughness and hydrogen content individually impact fatigue strength. Surprisingly, the fatigue strength of machined and polished samples, which aligns with standard testing practices, is significantly reduced, compared to other conditions. Fatigue cracks have been observed to initiate at the pores just below the as-cast surface or on the machined surfaces. In all cases, pores have been observed to be surrounded by bifilms. Moreover, hydrogen content and roughness of the as-cast surface have been found to interact to determine the fatigue performance. These findings necessitate a re-evaluation of fatigue testing procedures for cast aluminum components.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Bifilms, Fracture, Oxide skin, Pores, Weibull, Fatigue testing, Hydrogen, Magnesium alloys, Surface properties, Surface roughness, As-cast, Cast surface, Combined effect, Fatigue strength, Hydrogen contents, Machined surface, Oxide skins, Pore, Pore size
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-62484 (URN)10.1016/j.msea.2023.145618 (DOI)001087353900001 ()2-s2.0-85169977535 (Scopus ID)HOA;intsam;905111 (Local ID)HOA;intsam;905111 (Archive number)HOA;intsam;905111 (OAI)
Available from: 2023-09-19 Created: 2023-09-19 Last updated: 2023-11-21Bibliographically approved
Bogdanoff, T., Tiryakioglu, M., Liljenfors, T., Jarfors, A. E. .., Seifeddine, S. & Ghassemali, E. (2023). On the Effectiveness of Rotary Degassing of Recycled Al-Si Alloy Melts: The Effect on Melt Quality and Energy Consumption for Melt Preparation. Sustainability, 15(6), Article ID 5189.
Open this publication in new window or tab >>On the Effectiveness of Rotary Degassing of Recycled Al-Si Alloy Melts: The Effect on Melt Quality and Energy Consumption for Melt Preparation
Show others...
2023 (English)In: Sustainability, E-ISSN 2071-1050, Vol. 15, no 6, article id 5189Article in journal (Refereed) Published
Abstract [en]

The effectiveness of rotary degassing on the defect formation and mechanical properties of the final casting of aluminium alloy EN AC 46000 was investigated, along with its impact on the energy consumption in the casting furnace. In the melt preparation prior to casting, the molten metal is usually transported from the melting furnace to the casting furnace with rotary degassing as a cleaning procedure. Under the conditions of this specific study, negligible degradation was observed in the mechanical properties of the final cast component in an aluminium EN AC 46000 alloy after removing the rotary degassing step in the process. Furthermore, removing the rotary degassing step led to a reduced temperature drop in the melt, thus minimizing the need for reheating (energy consumption) by up to 75% in the casting furnace. The reduced energy consumption was up to 124,000 kWh in yearly production in a 1500 kg casting furnace. The environmental impact showed a similar to 1500 kg reduction in CO2 for one 1500 kg electrical casting furnace in a year.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
aluminium, sustainability, energy, casting, carbon footprint
National Category
Materials Engineering
Identifiers
urn:nbn:se:hj:diva-60220 (URN)10.3390/su15065189 (DOI)000960079100001 ()GOA;intsam;876312 (Local ID)GOA;intsam;876312 (Archive number)GOA;intsam;876312 (OAI)
Funder
Vinnova
Available from: 2023-04-21 Created: 2023-04-21 Last updated: 2023-11-21Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7527-719X

Search in DiVA

Show all publications