Effects of ultrasonic rolling on surface performance of 7B85-T6 alloy
Guanming Xu, Chunming Wang, Qiaoli Li, Xuehui Zhang, Zhu Zhiyun, Tongxiang Liang, Bin Yang
Abstract
Surface nanocrystallization (SNC) of 7B85-T6 alloy was obtained through ultrasonic surface rolling treatment (USRT) to improve the surface comprehensive performance of the alloy. The effects of USRT parameters on microhardness, surface roughness, and corrosion behavior of the 7B85-T6 alloy were investigated systemically. The optimal process parameters were obtained in the USRT process with the pressure of 0.3 MPa and the preloading depth of 0.2 mm. The microhardness and surface roughness of the alloy increased by 60.96% and reduced by 79% compared to the original alloy, respectively. Meanwhile, the corrosion resistance was improved in the 7B85-T6 alloy after USRT. The corrosion product film of the alloy after USRT was denser than that of the original alloy, which was attributed to the combined action between microstrain and nanograin. The phenomenon led to the enhanced surface activity and the formation of continuous dense Al2O3 oxides of the alloy.