Surface characteristics and corrosion behavior of TC11 titanium alloy strengthened by ultrasonic roller burnishing at room and medium temperature
Hao Su, Xuehui Shen, Chonghai Xu, Jianqun He, Baolin Wang, Guosheng Su
Abstract
A roller tip was utilized in a set of self-fabricated ultrasonic burnishing equipment. Ultrasonic roller burnishing with/without heat treatment was proposed and investigated in the surface strengthening of TC11 titanium alloy material. Experimental research together with finite element analysis were carried out to perform the study. Three treatments, including conventional turning, ultrasonic roller burnishing at ambient temperature (URB) and ultrasonic roller burnishing at medium temperature (URB/HT), were comparatively evaluated in term of surface integrity and corrosion resistance of the treated sample. As a result, compared with URB, the surface of TC11 alloy treated by URB/HT had better surface finishing, which significantly improved corrosion resistance, and thus the surface of TC11 alloy was strengthened. The good performance of URB/HT was attributed to the combined effect of the high frequency dynamic impact from URB and the thermoplastic effect of the heat treatment. Owing to the excitation of the ultrasonic vibration during URB, an oscillating stress wave formed and propagated deep inside the being treated material, and the heat treatment in URB/HT case was supposed to accelerate this sort of stress propagation. Meanwhile, both the heat treatment and the dynamic oscillating stress wave facilitated the deformation of the surface layer.