Annealing Treatment of Al2CoCrFeNi High-Entropy Alloys: Synergistic Effect of Microstructure Modulation on Mechanical and Thermoelectric Properties

This study synthesized Al2CoCrFeNi high-entropy alloy (HEA) using spark plasma sintering (SPS) followed by annealing treatment. The effects of heat treatment on the microstructure, mechanical properties, wear resistance, and thermoelectric properties were systematically investigated. The annealed alloy exhibited a microhardness increase from 538.5 HV to 550.9 HV and a significant improvement in ultimate compressive strength from 1540.74 MPa to 2563.67 MPa, attributed to grain homogenization and reduced dislocation density. Wear resistance tests revealed a decrease in wear rate from 7.15 × 10−5 mm3/(N·m) to 4.74 × 10−5 mm3/(N·m), with wear morphology analysis confirming enhanced resistance to plastic deformation. Thermoelectric characterization demonstrated that thermal diffusivity increased from 2.98 mm2/s to 3.11 mm2/s at room temperature, while the absolute Seebeck coefficient reached 8.0 μV/K at 200 °C, indicating improved electron transport efficiency due to lattice ordering. This combination of high hardness, high thermal conductivity, and excellent wear resistance presents unique application value in extreme tribological fields involving thermal management and simultaneous surface wear resistance and heat dissipation.