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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、160μm;显微硬度冲击一次后提升了29.2%,影响深度约为60μm。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 is a kind of surface treatment technology that can effectively improve the fatigue strength of materials. In view of the characteristics of K24 nickel-based superalloy simulation leaves, the paper proposed using unprotected laser shock to strengthen the surface treatment. At the same time, X-ray diffraction and microhardness tester were used to characterize the variation of residual stress and microhardness under different impact parameters. The strengthening effect was verified by high-frequency vibration fatigue test. The results show that the residual compressive stress is formed on the surface of the material without laser cladding after impact protection. The residual stresses after impacting for 1, 3 and 5 times are -428, -595 and -675 MPa, respectively. The influence depth is about 110,150,160μm; micro-hardness impact after a 29.2% increase, the impact depth of about 60μm. The fatigue strength of the simulated blade of K24 Ni-based alloy increased from 282 MPa to 327 MPa with an unequal impact, an increase of 16%.