A novel High-Entropy Alloy-based composite material

This study reports the results of the addition of different reinforcing agents (i.e. nano-diamonds, SiC, Sc2O3, h-BN, c-BN and CN) on the sintering process of the B2-structured Al2CoCrFeNi High-Entropy Alloy. The best candidate for further thermal, electrical and mechanical characterization was chosen to be the alloy containing 2 wt% nano-diamonds. The composite was prepared using spark-plasma sintering of pre-alloyed powders and characterized with SEM-EDX, DSC, Laser Flash Analysis (LFA), electrical conductivity and Seebeck coefficient, dilatometry, Young's modulus, Vicker's hardness, 3-points flexural test. It shows unexpectedly low thermal expansion coefficient (from 3×10−6 to 17×10−6 K−1 between RT and 500 °C), high electrical resistivity and Seebeck coefficient and hardness comparable to the sintered blank Al2CoCrFeNi.