激光冲击强化是一种有效提高材料疲劳强度的表面处理技术。针对K24镍基高温合金模拟叶片特点, 文中提出采用无保护层激光冲击强化进行表面处理。同时采用X射线衍射、显微硬度计表征了不同参数冲击下材料截面残余应力和显微硬度变化规律, 并利用高周振动疲劳试验验证其强化效果。结果表明: 无保护层激光冲击强化处理后在材料表层形成一定数值的残余压应力, 冲击1、3、5次后表面残余应力分别为-428、-595、-675 MPa, 影响深度分别约为110、150、160 μm; 显微硬度冲击一次后提升了29.2%, 影响深度约为60 μm。采用不等应力冲击后K24镍基合金模拟叶片疲劳强度由原始试件的282 MPa提高到327 MPa, 提高了16%。

Laser shock processing is a novel surface treatment technology to increase the fatigue strength of materials. Based on the characteristic of K24 nickelbased alloy simulation blades, the laser shock processing without coating (LSPwC) was carried out. Whilst the change discipline of micro-hardness and residual stress on the cross-section of K24 nickel-based alloy after different parameters of LSPwC were examined by micro-hardness tester and residual stress tester. In addition, the high cycle fatigue tests were conducted to verify the reinforcement effect. The experimental results show that particular compressive residual stress on the surface was induced by LSPwC, the largest residual stress value was -428, -595, -675 MPa with 110, 150, 160 μm depth affected layer under 1, 3, 5 impacts respectively. The surface micro-hardness was increased by 29.2% with 60 μm depth under one impact. The fatigue strength of simulation blades was improved from 282 MPa to 327 MPa, improved by about 16% after unequal stress impact.