Dislocation patterning in the TiZrVTa refractory high-entropy alloy under tribological loading

Investigation of the plastic deformation mechanism of refractory high entropy alloys (RHEA) under tribological loading is crucial to understanding their excellent tribological properties. In this study, the dislocation patterning and the dependence of scratch system between the TiZrVTa RHEA and pure Ta under tribological loading were compared through nanoscratching molecular dynamics simulation, and partial experimental verification was conducted. The results showed that TiZrVTa RHEA exhibits a stable and excellent tribological response, stemming from the stable dislocation length evolution and firm dislocation patterning caused by the significant pinning effect of lattice distortion and chemical composition fluctuations on dislocations. In particular, both pure Ta and RHEA exhibit strong dependence of scratch system on their tribological properties and dislocation patterning. Compared to pure Ta, RHEA has better tribological properties in any scratch system, and dislocation patterning is more concentrated at the scratching trace. An accident is the widespread expansion of dislocation patterning in RHEA when scratching along the slip system ((110)[1–10]), indicating that more favorable stress conditions can overcome the strong dislocation slip resistance in RHEA, leading to severe plastic deformation. This study aims to better understand the deep roots of excellent theoretical tribological properties of RHEA through dislocation patterning analysis, thereby promoting the development of RHEA with better tribological properties.