Microstructure and tribological properties of AlCoCrFeNiTi_0.5 high-entropy alloy in hydrogen peroxide solution

Microstructure and tribological properties of an AlCoCrFeNiTi_0.5 high-entropy alloy in high-concentration hydrogen peroxide solution were investigated in this work. The results show that the sigma phase precipitates and the content of bcc2 decrease during the annealing process. Meanwhile, the complex construction of the interdendrite region changes into simple isolated-island shape, and much more spherical precipitates are formed. Those changes of microstructure during the annealing process lead to the increase of hardness of this alloy. In the testing conditions, the AlCoCrFeNiTi _0.5 alloy shows smoother worn surfaces and steadier coefficient of friction curves than does the 1Cr18Ni9Ti stainless steel, and SiC ceramic preserves better wear resistance than ZrO₂ ceramic. After annealing, the wear resistance of the AlCoCrFeNiTi_0.5 alloy increases coupled with SiC counterface but decreases with ZrO₂ counterface.