Effects of service temperature on tensile properties and microstructural evolution of CP titanium subjected to laser shock peening

Effects of service temperature on the tensile properties and microstructural evolution of tensile specimens manufactured by commercial pure (CP) titanium subjected to laser shock peening (LSP) were investigated. Special attention was paid to the microstructural features at the top surface close to the fracture zone of the failed LSPed specimens at 20 °C, 150 °C, 250 °C, and 350 °C by means of transmission electron microscopy (TEM) observations. Results indicated that the ultimate tensile strength (UTS) of LSPed specimens gradually decreased, but the area reduction and elongation of LSPed specimens increased with the increment of service temperature. Furthermore, the influence mechanism of service temperature on the microstructural evolution of the LSPed CP titanium consisted of two modes: (a) ultra-high strain rate inhibited the dislocation motion at a lower temperature which was more prone to the occurrence of deformation twinning, and (b) ultra-high strain rate was easier to activate dislocation motion at a higher temperature, making deformation twinning disappear in the plastic deformation layer of CP titanium.