Effects of laser shock peening on the micro-hardness, tensile properties, and fracture morphologies of CP-Ti alloy at different temperatures

Abstract This study investigated the effects of laser shock peening (LSP) on the micro-hardness distribution and fractural morphologies of tensile specimens manufactured from commercial pure titanium (CP-Ti) at four different temperatures. The micro-hardness distributions and fractural morphologies of the as-machined and LSPed tensile specimens were characterized and analyzed. The relationship between the micro-hardness and microstructures of CP-Ti along the gauge length direction was also discussed. Results indicated that LSP significantly improved the micro-hardness of CP-Ti alloy; however, the high temperature negatively affected the micro-hardness but enhanced the plasticity of the product. Furthermore, LSP significantly increased the ultimate tensile strength (UTS), the area reduction of fracture surface, and the elongation rate of CP-Ti alloy. The high temperature induced tensile necking on the fracture surface and significantly promoted grain growth, thereby decreasing the UTS.