Iñaki Hurtado

This study develops novel multicomponent Al–Mg–Si–Zr–Cu-based alloys for high-pressure die casting (HPDC) with improved mechanical properties and thermal stability. Four compositions were designed through Zn and Cr additions, supported by thermodynamic modelling. XRD and SEM/EDS analysed phase formation and microstructure, while density, electrical conductivity, hardness, and mechanical behaviour under tensile and compressive loading at room temperature and 200 °C were evaluated. Hardness increased from 166 to 214 HV3 with Zn and Cr due to the formation of complex intermetallic phases. The Al–Mg–Si–Zr–Cu alloy showed the best balance of strength and ductility under tensile loading, whereas Zn and Cr additions reduced tensile performance. In compression, Zn significantly improved strength, reaching the ultimate compressive strength of 697 MPa. Compared with the reference AlSi9Cu3 alloy, the new alloys achieved up to 30% higher yield strength, 13% higher ultimate tensile strength, and improved thermal stability. Among the studied compositions, Al72Mg10Si5Zr3Cu10 showed the best overall performance, while Al67Mg10Si5Zr3Cu10Zn10 was optimal for compression-dominated applications.

This study develops novel multicomponent Al–Mg–Si–Zr–Cu-based alloys for high-pressure die casting (HPDC) with improved mechanical properties and thermal sta-bility. Four compositions were designed through Zn and Cr additions, supported by thermodynamic modelling. Phase formation and microstructure were analysed by XRD and SEM/EDS, while density, electrical conductivity, hardness, and mechanical behaviour under tensile and compressive loading at room temperature and 200 °C were evaluated. Hardness increased from 166 to 214 HV3 with Zn and Cr due to the formation of complex intermetallic phases. The Al–Mg–Si–Zr–Cu alloy showed the best balance of strength and ductility under tensile loading, whereas Zn and Cr additions reduced tensile performance. In compression, Zn significantly improved strength, reaching an ultimate compressive strength of 697 MPa. Compared with the reference AlSi9Cu3 alloy, the new alloys achieved up to 30% higher yield strength, 13% higher ultimate tensile strength, and im-proved thermal stability. Among the studied compositions, Al72Mg10Si5Zr3Cu10 showed the best overall performance, while Al67Mg10Si5Zr3Cu10Zn10 was optimal for compres-sion-dominated applications.

This paper presents and demonstrates the development of a new lightweight coating for aluminum alloy from a novel multicomponent alloy based on the AlSiMgCu system. The coating was applied using a newly designed approach that combined high velocity oxy-fuel (HVOF) and plasma spraying processes. This hybrid technique enables the deposition of coatings with enhanced performance characteristics. The optical microscopy (OM) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM + EDS) revealed a strong adhesion and compaction between the multicomponent coating and the A6061 substrate. The new coating improved hardness by 50% and increased electrical conductivity by approximately 3.3 times compared to the as-cast alloy. Corrosion tests showed a lower corrosion rate, comparable to thermally treated A6061 alloy. Tribological tests indicated over 20% reduction in friction and over 50% reduction in wear rate. This suggests that multicomponent aluminum coatings could improve automotive and parts in contact with hydrogen by enhancing hydrogen fragilization resistance, corrosion resistance, electrical conductivity, and wear properties, with further optimization of thermal spraying potentially boosting performance even further.

This paper presents and demonstrates the development of a new lightweight coating for aluminium alloy using a novel multicomponent alloy based on the AlSiMgCu system. This coating was applied using a newly designed approach that combined High-Velocity Oxy-Fuel (HVOF) and Plasma Spraying processes. This hybrid technique enables the deposition of coatings with enhanced performance characteristics. The microstructure was studied using optical microscopy (OM) and scanning electron with energy dispersive X-ray spectroscopy (SEM+EDS) microscopy, revealing good adhesion and compaction between the multicomponent coating and the A6061 substrate with 50 to 150 µm thickness. Vickers indentations were performed on the substrate and the new coating material, revealing a 50% improvement in the material's hardness compared to the casted alloy. Additionally, electrical conductivity measurements showed approximative x3.3 times values compared to the alloy in as-cast condition due to high solidification rates altering the morphology of the phases. Corrosion tests demonstrated a lower corrosion rate compared to other multicomponent aluminium alloys and similar to thermal treated A6061 alloy. Finally, tribological results obtained using ball on disc (BOD) test and laser scanning confocal microscopy, confirmed that the new multicomponent coating exhibited reductions in both friction coefficient and wear rate by more than 20% and 50%, respectively. This study demonstrates that using multi-component aluminium coatings could lead to developing of new automotive parts with enhanced properties for corrosion resistance, electrical conductivity, and wear conditions. Optimizing the thermal spraying parameters could further enhance the coating, achieving greater and more homogeneous thicknesses and yielding even higher performance properties.

In this study, the Near Solidus Forming (NSF) process, which falls under the umbrella of semi-solid processes, was utilized to coforge an AISI 316 tube and an AISI 3415 rod into an as-forged valve geometry. The billet used for the process was kept as large as possible to increase the contact surface area between the two materials. The process was carried out at 1360 °C in a single stroke, almost completely filling the geometry. No joining was observed in areas where low strains were expected, but in regions with medium to high strains, cross-diffusion of 2–7 μm was observed. The presence of small oxide particles was also observed in the joint due to the bimetallic billet shape.