No abstract

In this study, the effects of Cu addition on AlFeMnTiSi 0.75 Cu x (x = 0, 0.25, 0.5, 0.75, 1.00; in molar ratios) high entropy alloys (HEAs) prepared via mechanical alloying and spark plasma sintering were investigated. The structure, phase, morphology and composition of HEA powders were analysed and the results revealed that the AlFeMnTiSi 0.75 Cu x HEAs exhibited a multiphase structure. Additionally, after sintering at 900 °C, the formation of BCC, µ and L2 1 phases in the densified HEAs was enhanced. The investigation of the hardness, nanoindentation and compressive properties revealed that the microstructural and mechanical properties of AlFeMnTiSi 0.75 Cu x HEAs were improved at the optimal Cu fraction (0.25 molar ratio). The nanoindentation results revealed that the AlFeMnTiSi 0.75 Cu x HEAs exhibited the highest hardness and elastic modulus (H IT = 19.2 GPa, E IT = 336 GPa). These results improve the current understanding of multiphase HEAs and may pave way for the development of advanced HEAs with superior mechanical properties.

In this study, dry sliding wear of AlSi 0.75 TiMnFeCu x (x = 0, 0.25, 0.5) high-entropy alloy (HEA) produced through mechanical alloying (MA) and spark plasma sintering (SPS) was studied. The microstructure and phase evolution were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The wear behaviour of HEAs was assessed by reciprocating wear monitor under a dry air atmosphere. The findings demonstrated that AlSi 0.75 TiMnFeCu x HEAs were multiphase body-centred cubic (BCC/B2) solid solution structured with complex µ-, L 21 , and Laves. It was discovered that the microhardness and wear behaviour of AlSi 0.75 TiMnFeCu x were comparable to AlSi 0.75 TiMnFe HEA after the addition of Cu up to 0.25 molar ratio. The maximum hardness of the AlCu 0-0.5 FeMnTiSi 0.75 HEAs reached around 1021-1035 HV. The tribology results show that an oxidative wear in AlSi 0.75 TiMnFe while the mixed adhesive-abrasive wear mechanism was prominent in the AlSi 0.75 TiMnFeCu 0.25-0.5 HEAs.