激光冲击强化的微观组织演变与性能研究进展

Microstructure Evolution and Performance Enhancement of Laser Shock Peening

激光冲击强化(LSP)是一种利用激光诱导等离子体冲击波来提高材料疲劳寿命的新型表面改性技术,通过冲击波的力学作用使材料表面发生高应变速率的塑性变形,可以显著改善基体材料表面微观组织,实现晶粒细化,提高位错密度,形成位错缠结、位错壁等结构。在LSP基础上开展的热激光冲击强化(WLSP)和深冷激光冲击强化(CLSP)可以进一步通过动态应变时效(DSA)效应、动态沉淀(DP)效应、高密度形变孪晶以及堆垛层错等方式提高基体材料残余应力的稳定性。基于金属表面微观组织状态的演变规律,LSP技术可以显著提高材料的硬度和屈服强度,有效改善部件的工作稳定性。还可以改善材料的耐腐蚀性能,显著提高材料的疲劳寿命,进而拓宽LSP处理材料的应用领域。

Laser shock peening(LSP)is a new surface modification technology that uses laser-induced plasma shock waves to improve the fatigue life of materials.Through the mechanical action of shock waves,the plastic deformation of materials surface occurs at a high strain rate,which can significantly improve the surface microstructure of materials,realize grain refinement,increase dislocation density,and form dislocation tangles,dislocation walls as well as other structures.Based on LSP,warm laser shock peening(WLSP)and cryogenic laser shock peening(CLSP)can further improve the residual stress stability of materials by dynamic strain aging(DSA)effect,dynamic precipitation(DP)effect,high-density deformation twinning,and stacking faults.Based on the evolution of the microstructure of metal surface,LSP technology can significantly increase the hardness and yield strength of material,thereby effectively improve the working stability of component.In addition,LSP technology can also enhance the corrosion resistance and fatigue life of materials to broaden the application field of LSP processing materials.