Study On Strengthen Mechanism And Life Extension Mechanism Of Double Phase Titanium Alloy TC17 With Laser Shock Peening

Dual phase titanium alloy TC17 has excellent mechanical properties,with an alternative in the aviation industry.It has been widely used in aircraft engines and other ker components.Laser shock peening(LSP)can effectively improve the performance of TC17 alloy,especially fatigue performance.However the mechanism of LSP need to be explained more comprehensively.Theoretical deduction,numerical simulation and experimental study have been used in this paper to deeply investigate the dynamic response characteristics and fatigue properties of TC17 alloy.The mechanism of LSP and life extension are further revealed and the theoretical basis is enriched.The following work has been carried out aiming at the above objectives.The propagation law of stress wave in TC17 alloy with no reflection condition and reflection condition has been studied systematically.The propagation law of stress wave and the dynamic response mechanism of stress wave have been revealed.Based on the formation mechanism of residual stress field,the numerical simulation method has been used to simulate the stress wave.The effects of LSP path,single and double sided LSP,curvature radius and LSP temperature on the residual stress field are elucidated by studying the distribution of residual stress field under different LSP modes.Based on the theory of fracture mechanics,the law of fatigue life under the condition of non-LSP and LSP condition has been deduced.The fatigue properties of single-jointed tensile test specimen are studied by experiments and MSC.Fatigue numerical analysis.The results show that the residual stress of the specimen increases with the increase of the LSP temperature in a certain range.LSP can improve the fracture toughness of the material and extend fatigue life of the material.The research results will contribute to the improvement of Chinese LSP technology database and guidance of technology application.