A Systematic Study of Multiple Strengthening Effects on Wear Behavior of Tixcrnbtawy Refractory High-Entropy Composites: Inducing Amorphization to Achieve Anti-Wear

Abstract

Refractory high-entropy alloys (RHEAs) possess exceptional properties at elevated temperatures. However, their limited wear resistance at room temperature (RT) hinders their widespread application. Here, a series of TixCrNbTaWy (x=1, y=0, 0.5 and 1; x=1.5, y=1) refractory high-entropy composites (RHEACs) coexisting with multiple strengthening mechanisms have been successfully fabricated using spark plasma sintering. Attributed to the corporate strengthening effect of in-situ ceramic phases with high hardness (21 GPa) and intensified solid-solution strengthening induced by Ti/W elements, the Ti1.5CrNbTaW RHEAC achieves an optimal yield strength of 2.13 GPa, along with a low wear rate of 4.9 ×10-5 mm3/(N·m), which is 82% lower compared to the original TiCrNbTa RHEAC. The wear mechanism is attributed to the formation of a protective oxidized amorphous layer supported by the decreased amorphization critical size, which is found firstly in bulk RHEACs. Theoretical calculations show this critical size is proportional to the solid solubility of the RHEACs matrix. This simple and practical strategy provides a new strategy for designing robust anti-wear RHEACs at RT.

Keywords: refractory high-entropy alloys, multi-strengthening mechanisms, wear properties, friction-induced amorphization