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为了揭示激光喷丸(LP)强化IN718合金疲劳寿命增益的机制,研究了合金喷丸前后晶粒重排与疲劳特性的关系。结果表明,LP后试样表层的塑性形变深度最大可达33.7μm,合金的最大疲劳寿命增益可达188%;激光冲击波诱导产生的表层残余压应力随激光功率密度的增大而增大,但增幅逐渐减小;疲劳试验后,表层残余应力出现了52%的释放;LP后试样表层晶粒出现细化现象,细化深度达到175μm;位错滑移和位错攀移以及孪晶等共同作用使原始晶粒内形成了亚晶粒,最终细化了晶粒组织。
In order to reveal the mechanism of laser shot peening (LP) strengthening the fatigue life of IN718 alloy, the relationship between the grain rearrangement and fatigue characteristics before and after shot peening was studied. The results show that the depth of plastic deformation of the sample surface after LP is up to 33.7μm, and the maximum fatigue life gain of the alloy is up to 188%. The surface residual compressive stress induced by laser shock wave increases with the laser power density increasing After fatigue test, the surface residual stress appeared 52% of the release; LP after grain surface grain refinement phenomenon, the depth of 175μm; depth of dislocation slip and dislocation climbing and twins Together, the subgrains are formed within the original grains, eventually refining the grain structure.