Stress Wave and Residual Stress Characteristics of TC17 Titanium Alloy Subjected to Warm Laser Shock Peening

Abstract

Compared with Laser Shock Peening (LSP), Warm Laser Shock Peening (WLSP) can obtain higher residual stress, hardness, dislocation density, and finer grain. In this paper, the dual phase titanium alloy TC17 is studied. WLSP tests of TC17 specimen under different temperatures are carried out. The surface residual stress of the specimen is measured by XRD method, and residual stress distribution of the specimen is also numerically analyzed. It is found that the numerical results are in good agreement with the experimental results. Numerical results further show that the peak residual stress (−340 to −480 MPa) of the specimen increases with increased temperature. The stress wave gradually decreases along the thickness direction during the impact process, but it abruptly increases at the bottom of the specimen because of reflection. The equivalent plastic strain of the specimen increases with increased temperature. The dynamic yield strength (−1831.1 to −1468 MPa) of the material is calculated by deducing, which decreases with increased temperature. When the temperature is higher than 750 °C, residual stress hole phenomenon occurs, and the residual stress decreases with a further increment of the temperature. In addition, the influence of laser power, impact times, and overlapping rate on residual stress is also studied.