Microstructure evolution and mechanical properties of CoCrFeMnNi HEA-MXene composites prepared by spark plasma sintering

In this work, the influence of different MXene weight percentages (0, 2, 4, 6 & 10 wt%) on the microstructure, wear behavior, and mechanical properties of CrMnFeCoNi High Entropy Alloy (HEA) were investigated. The CrMnFeCoNi HEA powder and Ti3C2Tx MXene phase were prepared by the gas atomization process and selective etching of the aluminum layer of MAX phase (Ti3AlC2), respectively. Bulk samples of CrMnFeCoNi HEA and HEA matrix-MXene composites were prepared by spark plasma sintering (SPS) using a mixture of CrMnFeCoNi HEA powder that contained 2 wt%, 4 wt%, 6 wt%, 10 wt% of MXene phase. The microstructure evolution, phase structure, and compressive mechanical properties of the samples were investigated at room temperature. It was observed that the CrMnFeCoNi HEA forms a single-phase FCC structure after the gas atomization and SPS process, while the microstructure of the HEA-MXene composites consisted of FCC and HCP phases. The fractions of the MXene phase played important roles in the nanostructural evolution and grain refinement of the HEA-MXene composites. The results of mechanical tests indicated that the micro-hardness of CrMnFeCoNi increased from 205.8 HV to 617.6 HV and the yield strength increased from 390 MPa to 1403 MPa with the addition of 10 wt% MXene phase. Moreover, the addition of MXene led to a significant increase in wear resistance and a decrease in the coefficient of friction. The attractive mechanical properties of the HEA-MXene composites were attributed to the grain refinement effect induced by the MXene phase. •This study highlights the role of MXene fractions in optimizing the performance of High Entropy Alloy-based composites.•Transformative impact of Ti₃C₂Tₓ MXene on performance of CrMnFeCoNi HEA composites was comprehensively analyzed.•MXene phases, prepared by selective etching of the aluminum layer from Ti₃AlC₂ MAX phase, were incorporated into the HEA matrix.•Addition of MXene resulted in significant grain refinement thus enhancing the wear resistance and mechanical properties of HEA composites.