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为了研究激光冲击强化技术在高温部件上应用的可行性,研究了GH4133镍基高温合金激光冲击后强化效果的热稳定性。分别采用激光冲击强化、激光冲击强化加保温的方法进行处理,并利用SEM、显微硬度和残余应力的测试方法分析了温度对激光冲击处理后GH4133材料微观组织和力学性能的影响。通过冲击强化后涡轮叶片的高温疲劳试验验证强化效果的热稳定性,并分析其高温下的强化机制。结果表明,激光冲击强化可以在GH4133镍基高温合金表层产生较大残余压应力,细化晶粒;并且在温度作用下,激光冲击GH4133合金形成的细化晶粒在析出相的钉扎作用下具有较好的热稳定性。另一方面残余压应力的应力集中减小,分布均匀。两者的共同作用提高了强化效果的热稳定性,有利于疲劳性能的提高。
In order to study the feasibility of applying laser shock enhancement technology to high temperature components, the thermal stability of GH4133 nickel base superalloy after laser shock was studied. The effects of temperature on the microstructure and mechanical properties of GH4133 after laser shock treatment were analyzed by using SEM, microhardness and residual stress test methods respectively by laser shock and laser shock strengthening plus heat preservation. The thermal stability of the strengthening effect was verified by the high-temperature fatigue test of the turbine blades after impact strengthening, and the strengthening mechanism under high temperature was analyzed. The results show that laser shock strengthening can produce large residual compressive stress on the surface layer of GH4133 nickel base superalloy and refine the grains. Under the action of temperature, the laser shocks the refined grains formed by the GH4133 alloy under the pinning effect of precipitation phase Has good thermal stability. On the other hand, the compressive stress of residual compressive stress decreases and distributes evenly. The combined effect of the two enhances the thermal stability of the strengthening effect and is conducive to the improvement of fatigue properties.