The modified wear resistance of uranium induced by ultrasonic surface rolling process

With the development of the nuclear industry, uranium materials with better wear resistance are demanded. This paper aims to demonstrate the effects of ultrasonic surface rolling process (USRP) on the tribological properties of uranium. Surface characteristics, i.e., surface topography, residual stress, microstructure, hardness and wear behavior, were examined. The results indicated that nanostructure, deformation twins and texture were generated on the uranium surface after USRP treatment. Surface roughness Ra, Rp and Rv showed a remarkable decline by 85.6%, 85.5% and 74.8% compared to the untreated specimen, respectively. Moreover, increased microhardness and enhanced residual compressive stress were obtained by USRP treatment. According to the wear tests against silicon carbide counterball in dry sliding conditions, the friction coefficient was decreased to 0.66 and the wear volume was also drastically reduced, which prolonged the friction and wear life of uranium materials. Additionally, it was concluded that abrasion wear, adhesion wear and oxidation wear played the dominant roles in the USRP treated specimens and the silicon carbide counterball showed the characteristics of abrasion wear.