Microstructure, mechanical and wear properties of AZ31/CoCrFeNi composites fabricated by friction stir processing

AZ31 magnesium (Mg) alloy composites reinforced with CoCrFeNi high-entropy alloy (HEA) particles were fabricated by friction stir processing (FSP). OM, SEM, EDS, and EBSD were used to characterize the microstructure of composites. Mechanical and wear properties of the composites were investigated by tensile, microhardness, and dry sliding wear tests. The results revealed that HEA particles were homogeneously distributed and exhibited good metallurgical bonding with Mg matrix. The yield strength, ultimate tensile strength, and microhardness of the composites were 80 MPa, 46 MPa, and HV 54.9 higher than those of the base metal (BM), respectively. Fine-grained strengthening was the main strengthening mechanism whose contribution rate on the yield strength was 43.9%. The average friction coefficient of the composites was decreased from 0.331 of BM to 0.240, and the wear mechanism was changed from adhesive wear of BM to abrasive wear.