Synergistic enhancement of 7075 aluminum alloy composites via high entropy alloy particle integration: Microstructural and mechanical insights

This study investigates the impact of high-entropy alloy (HEA) particle reinforcement on the microstructure, mechanical properties, and performance of 7075 aluminum matrix composites (AMCs). Utilizing spark plasma sintering (SPS), composites with varying HEA particle concentrations were synthesized to assess their effects comprehensively. The results indicate that increasing HEA content significantly enhances the density and hardness of the composites. Specifically, a 20 wt% HEA reinforcement achieved a high hardness of 61 HRB and a density of 3.21 g/cm³. The compressive strength initially increased with HEA content but then decreased as it ranged from 5 wt% to 20 wt%. Optimal mechanical properties, including a compressive strength of 680 MPa and a fracture elongation of 33 %, were observed at 10 wt% HEA. Wear testing further demonstrated the advantages of HEA reinforcement, with a substantial reduction in wear rate from 9.97 ± 1.1 × 10⁻⁴ to 2.06 ± 0.1 × 10⁻⁴ mm³/N·m at 10 wt% HEA. Additional analyses using energy-dispersive X-ray spectroscopy (EDX) and nanoindentation identified an aluminum-rich transition layer at the HEA-aluminum interface, formed due to aluminum diffusion. This transition layer likely enhances interfacial wettability and bonding, contributing to the improved performance of the composite.