The study of mechanical and tribology properties at room- and high-temperature in a (NiCoFe)86.5(AlTi)12(WMoV)1.5 high-entropy alloy

Abstract

In this study, we prepared (NiCoFe) 86.5 (AlTi) 12 (WMoV) 1.5 HEA with excellent mechanical properties and tribological properties by vacuum arc melting technology. The results show that the fracture mechanism of the alloy at ambient temperature was ductile fracture, while at high temperature was cleavage fracture. The wear mechanisms of the alloy include abrasive wear and oxidative wear, delamination wear and adhesive wear. The alloy has the excellent tribology property and a good combination of strength and ductility. This enhancement is attributed to the alloy having a relatively high-volume fraction of nano-L1 2 precipitates, which can effectively hinder the movement of dislocations. The precipitates are highly coherent with the matrix, which can effectively reduce the mismatch degree and the distortion energy of HEA, so the stress concentration problem between the precipitates and the matrix is effectively avoided, thereby improving the strength and wear performance of the alloy. The existence of annealing twins can play a role in grain refinement. During plastic deformation, the dislocation movement can be effectively hindered, and the occurrence of work hardening phenomenon can be delayed to a certain extent, so that the plastic deformation can continue, and play a key role in the wear performance of the alloy. In addition, we found that the oxide film formed on the worn surface of the alloy is more brittle at low temperatures. When the temperature reaches 773 K, a tougher oxide enamel layer was formed on the worn surface, which greatly improves the wear performance of the alloy at high temperatures. • (NiCoFe) 86.5 (AlTi) 12 (WMoV) 1.5 HEA with excellent mechanical properties and tribological properties was fabricated. • Tensile properties at room- and high-temperature. • Tribological properties at room- and high-temperature.