Introduction of Compressive Residual Stress into Titanium Alloy Ti6Al4V by Cavitaion Shotless Peening
Hitoshi SOYAMA, Dan ODHIAMBO and Shankar MALL
Abstract:Cavitation impacts induced by a submerged water jet with cavitation, i.e. a cavitating jet, can introduce the compressive residual stress into metals as same way as shot peening. In case of peening by using cavitation impacts, shots are not required, then it is called cavitation shotless peening CSP. The blade/disk dovetail joint in turbine engine commonly fails due to fretting fatigue. The introduction of the compressive residual stress is the most significant factor in improvement of fretting fatigue behavior of metals. In order to investigate the possibility of CSP on reduction of fretting fatigue of titanium alloy, Ti6Al4V, the residual stress of the titanium alloy peened by CSP was measured by using an X-ray diffraction method. It was concluded that CSP can introduce the compressive residual stress into the titanium alloy. The compressive residual stress at the surface peened by CSP is larger than that of shot peening and the roughness of CSP is smoother than that of shot peening. Key Words:Residual stress, Surface modification, Titanium, Cavitation, Peening, Surface roughness