A non-equiatomic Ni-Co-Fe medium-entropy alloy with excellent wear resistance and strength-ductility combination by adding Al

In this work, a series of Al-doped AlxNi0.6CoFe1.4 (x = 0, 0.1, 0.2 and 0.3) medium-entropy alloys (MEAs) were prepared to investigate the mechanical and wear performances. The results reveal that the phase structure of AlxNi0.6CoFe1.4 MEAs is composed of disordered body-centered cubic (BCC) phase with a minor amount of ordered BCC (B2) phase after addition of Al. The mechanical tests show that the micro-hardness, tensile strength and fracture elongation initially increase and then decrease with increasing Al content. Specifically, the Al0.2 alloy exhibits the optimum mechanical properties, with the highest micro-hardness of 732.7 +/- 16.1 Hv, the maximum tensile strength of 1103.6 +/- 20.5 MPa and the maximum fracture elongation of 13.6 +/- 0.9%, respectively. In addition, all Al-doped AlxNi0.6CoFe1.4 alloys exhibit a higher wear resistance compared with the Al-free Ni0.6CoFe1.4 alloy at dry sliding. The underlying mechanisms for the Al effect on the mechnical properties and wear resistance of AlxNi0.6CoFe1.4 MEAs were uncovered.

Automated summary

Investigated the effects of aluminum doping on the mechanical and wear properties of medium-entropy alloy AlxNi0.6CoFe1.4. Found that aluminum addition can enhance the mechanical properties and wear resistance, with the Al0.2 alloy exhibiting the best overall performance.