Laser shock peening (LSP) is a mechanical surface treatment which can induce large compressive residual stresses and microstructural changes in a material by using repetitive shocks from laser pulses. In this work, the surface integrity (surface microstructure, topography, hardness and residual stress) of a LSP-treated powder metallurgy Ni-based superalloy was investigated for the first time. LSP treatment introduced large plastic deformation especially at a depth of about 100 μm from the surface, which increased the local hardness. The residual stress from the surface to the interior of the sample was investigated by synchrotron x-ray diffraction. The maximum compressive stress reached 400 MPa at the surface, while the depth of the compressive stress is about 0.7 mm. Lastly, the oxidation behavior of the treated and untreated samples was evaluated by thermal exposure at 700°C for 312 h. The LSP treatment decreased the thickness of the oxide layer, thereby showing improved oxidation resistance.

中文翻译：

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激光冲击强化处理粉末冶金镍基高温合金的表面完整性和氧化

激光冲击强化 (LSP) 是一种机械表面处理，可通过使用激光脉冲的重复冲击在材料中引起较大的压缩残余应力和微观结构变化。在这项工作中，首次研究了经 LSP 处理的粉末冶金镍基高温合金的表面完整性（表面微观结构、形貌、硬度和残余应力）。LSP 处理引入了较大的塑性变形，特别是在距表面约 100 μm 的深度处，这增加了局部硬度。通过同步辐射X射线衍射研究了从样品表面到内部的残余应力。表面最大压应力达到400 MPa，压应力深度约为0.7 mm。最后，通过在 700°C 下热暴露 312 小时来评估处理和未处理样品的氧化行为。LSP处理降低了氧化层的厚度，从而表现出提高的抗氧化性。