中文摘要：

激光吃惊 peening (LSP ) 是能有效地改进疲劳生活和金属部分的影响坚韧的一种广泛地使用的表面处理技术。Cr5Mo1V 钢展出一个坡度在一个 LSP 过程以后的变硬的层。一个新方法被建议估计在坡度认为变化是机械性质的影响坚韧变硬层。假定一线性地影响坚韧的坡度分发，控制坡度的影响坚韧的参数变硬层被给。激光力量密度的影响和影响坚韧上的激光射击的数字被调查。peened 层与一个未经治疗的标本相比改进的激光的影响坚韧，和影响坚韧与激光射击的数字与激光力量密度和减少增加。通过由一台扫描电子显微镜的破裂形态学分析，我们证实 Cr5Mo1V 钢被与一些酒窝相结合的劈开破裂机制折断。因为减少的尺寸，在 LSP 以后的材料的影响坚韧的增加被观察并且在坡度增加了劈开破裂的部分变硬的层。

英文摘要：

Laser shock peening（LSP） is a widely used surface treatment technique that can effectively improve the fatigue life and impact toughness of metal parts.Cr5Mo1 V steel exhibits a gradient hardened layer after a LSP process.A new method is proposed to estimate the impact toughness that considers the changing mechanical properties in the gradient hardened layer.Assuming a linearly gradient distribution of impact toughness,the parameters controlling the impact toughness of the gradient hardened layer were given.The influence of laser power densities and the number of laser shots on the impact toughness were investigated.The impact toughness of the laser peened layer improves compared with an untreated specimen,and the impact toughness increases with the laser power densities and decreases with the number of laser shots.Through the fracture morphology analysis by a scanning electron microscope,we established that the Cr5Mo1 V steel was fractured by the cleavage fracture mechanism combined with a few dimples.The increase in the impact toughness of the material after LSP is observed because of the decreased dimension and increased fraction of the cleavage fracture in the gradient hardened layer.