The influence of residual compressive stress (RCS) depth and magnitude generated through surface treatments such as shot peening (SP), deep cold rolling (DCR), and vibro‐peening (VP) on fatigue crack mechanisms of Ni‐based superalloy is investigated. The fatigue performance with associated failure mechanisms is measured under strain‐controlled fatigue testing upto 10⁴ cycles with total strain in the range of 0.9%–1.4% at an R ratio of 0.1 and 400°C followed by load controlled fatigue until failure. In‐depth understanding of the failure mechanism is obtained through fractography analysis, cyclic stress–strain plot, and microstructural features. A pronounced improvement in fatigue life tested at low strain range (0.9%–1.1%) is achieved after inducing RCS up to 400 μm depth. However, the fatigue life is reduced when RCS increased to 800–1000 μm depth. Failure is primarily driven by micro‐cracks formed due to balancing tensile stresses and high intensity stress concentration generated as the result of dislocation pile‐ups and slip bands. Results are discussed in detail through the evidence of grain refinement, addition of low angle grain boundaries (LAGBs), strain accumulation, and intragranular deformation in the sub‐surface.

中文翻译：

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残余应力分布和显微组织特征对镍基高温合金疲劳破坏机理的影响

研究了通过表面喷丸处理（SP），深冷轧制（DCR）和振动喷丸处理（VP）等表面处理产生的残余压应力（RCS）深度和强度对镍基高温合金疲劳裂纹机理的影响。在高达10 ^4的应变控制疲劳测试下测量了带有相关故障机制的疲劳性能 在0.1和400°C的R比下，总应变在0.9％–1.4％的范围内循环，然后进行负载控制的疲劳直到失效。通过断裂形貌分析，循环应力应变图和微观结构特征，可以深入了解破坏机理。在诱导高达400μm深度的RCS后，在低应变范围（0.9％–1.1％）下测试的疲劳寿命有了显着改善。但是，当RCS增加到800–1000μm深度时，疲劳寿命会降低。失效的主要原因是由于位错堆积和滑移带产生的平衡拉伸应力和高强度应力集中而形成的微裂纹所致。通过晶粒细化，添加低角度晶界（LAGB），应变累积，