一种利用水下激光冲击处理涡轮叶片残余应力的方法

为提高涡轮叶片疲劳寿命,探索了一种利用水下激光冲击强化方法处理涡轮叶片残余应力的技术。利用波长532 nm、脉宽10 ns、能量1.2~1.5 J、光斑直径1.0 mm的YAG激光器,对涡轮叶片榫齿部位进行了激光冲击强化处理。结果表明,水下激光冲击强化方法能有效消除、调整机械加工残余应力。当激光功率密度大于2.5 GW/cm^2且小于7.5 GW/cm^2时,随着功率密度的增加,表面残余应力也相应增加;当功率密度大于10.0 GW/cm^2后,表面残余压应力随功率密度的增加而明显降低;功率密度等于7.5G W/cm^2时,表面残余应力为-419.5 MPa,为最佳。

A method of relieving residual stress of the turbine blade by laser shock peening in water

In order to improve the fatigue strength of turbine blade,the blade laser shock peening(LSP)method was studied.The turbine blade root was treated with YAG laser,by using the laser wavelength of 532 nm,plus width of 10 ns,energy of 1.2~1.5 J,and spot diameter of 1.0 mm.The results indicate that the LSP relieves and adjusts residual stress.For the laser power density range I 0,when 7.5 GW/cm 2>I 0>2.5 GW/cm^2,with the increasing of the power density,the surface residual stress also increases accordingly.When the power density above 10.0 GW/cm^2,surface residual compressive stress decreases significantly as power density continues to increase.In the case of I 0=7.5 GW/cm^2,the surface residual stressσ=-419.5 MPa is the best parameter.