Ultrasonic rolling strengthening of TC11 titanium alloy surface: Corrosion and wear properties under extreme conditions

Abstract

The surface of TC11 titanium alloy was polished and strengthened using ultrasonic rolling process (USRP) technology. The effects of USRP on the surface quality, friction and wear properties, corrosion resistance, and wear mechanisms of TC11 titanium alloy at room temperature, low temperature (−60 °C), high temperature (400 °C), and in corrosive environments were investigated by using optical microscope, microhardness tester, electrochemical workstation, multifunctional friction and wear tester, SEM, EDS, XRD, and XPS. The results indicate that USRP can effectively refine the surface grains of titanium alloy, reducing its surface roughness parameter by 80.4 % and increasing surface hardness and residual compressive stress by 21.7 % and 97.1 %, respectively. USRP is advantageous for producing a layer of TiO2 on the surface of titanium alloys, effectively enhancing the corrosion resistance of titanium alloy surfaces. USRP technology can improve the stability of surface hardness values of titanium alloys in harsh environments. The results of dry friction and wear tests using GCr15 steel balls as the counter material show that the USRP technology can effectively reduce the friction coefficient and wear loss at room, high and low temperatures. The results of corrosion and wear tests using Si3N4 as the counter material indicate that the USRP technology can effectively reduce the friction coefficient and wear volume in seawater corrosion environments. The USRP technology is most effective in reducing the high-temperature friction coefficient of titanium alloys and improving their wear resistance in low-temperature and corrosive environments. The primary wear form of TC11 titanium alloy after USRP has shifted from adhesive wear to abrasive wear.