Tool wear mechanism of machining refractory high-entropy alloys

Abstract

Refractory high-entropy alloys (RHEAs) have broad application prospects due to its excellent mechanical properties, yet there is little information about its cutting process. And the excellent mechanical properties would accelerate the tool wear during the cutting process. Therefore, the tool wear behavior of machining RHEAs at different cutting speeds was investigated in this work. The results showed that adhesive wear and diffusion wear were the main wear mechanisms. With the increase of cutting speed, the high temperature led to the thermal softening of material, and the material adhered to the tool surface under the effect of high pressure, resulting in adhesive wear. Meanwhile, with the increase of cutting speed, the adhesive accumulation on the flank face became obvious, which aggravated the adhesive wear. In addition, the Zr, Mo and Nb elements were detected in the internal cross section of the tool, indicating that there was diffusion wear. And it was the most serious on the flank face. With the increase of cutting temperature, the diffusion depth also increased. Moreover, a tool flank wear rate model was established, and the prediction error was within 5 %. Based on the wear rate model, the diffusion wear rate increased significantly with the increase of cutting temperature. And the adhesive wear rate was always larger than the diffusion wear rate.