Abstract Surface treatments such as shot peening to inhibit fatigue crack initiation are essential processes when designing gas turbine components for aerospace applications. It is therefore crucial to understand the effects of shot peening in representative service environments. Here, the influence of surface treatment on the high temperature corrosion fatigue response of a polycrystalline nickel-based superalloy is considered, an area that has not previously been explored. Two shot peening conditions; 110H 7A 200% and 330H 7A 200%, along with a polished surface were chosen. Specimens were salted and exposed to SO2 gas during fatigue testing at 700 °C. A range of novel techniques including SEM, EBSD and axial chromatism profilometry were used to analyse the near surface cold work and surface condition before and after testing. EBSD local misorientation maps, paired with an increase in corrosion-fatigue life, suggest that a greater depth of cold work produced by the smaller shot size (110H), is providing a significant benefit in terms of hot corrosion and corrosion-fatigue performance. This paper concludes that the presence of a substantial layer of cold work is required to account for any metal loss due to the effects of hot corrosion. It is also evident that cold work hinders fatigue crack initiation and delays the onset of pit to crack transition.

中文翻译：

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近表面塑性变形对镍基高温合金热腐蚀和高温腐蚀疲劳响应的影响

摘要 在设计用于航空航天应用的燃气轮机部件时，表面处理如喷丸处理以抑制疲劳裂纹萌生是必不可少的过程。因此，了解喷丸强化在代表性服务环境中的影响至关重要。在这里，考虑了表面处理对多晶镍基高温合金的高温腐蚀疲劳响应的影响，这是以前未曾探索过的领域。两种喷丸条件；选择了 110H 7A 200% 和 330H 7A 200% 以及抛光表面。在 700 °C 的疲劳测试期间，样品被盐渍并暴露于 SO2 气体中。包括SEM、EBSD和轴向色差轮廓仪在内的一系列新技术被用于分析测试前后的近表面冷加工和表面状况。EBSD 局部错误取向图与腐蚀疲劳寿命的增加相结合，表明较小的注射尺寸 (110H) 产生的冷加工深度更大，在热腐蚀和腐蚀疲劳性能方面提供了显着的好处。本文得出的结论是，需要大量冷加工来解决由于热腐蚀影响造成的任何金属损失。同样明显的是，冷加工阻碍了疲劳裂纹的萌生并延迟了凹坑到裂纹过渡的开始。本文得出的结论是，需要大量冷加工来解决由于热腐蚀影响造成的任何金属损失。同样明显的是，冷加工阻碍了疲劳裂纹的萌生并延迟了凹坑到裂纹过渡的开始。本文得出的结论是，需要大量冷加工来解决由于热腐蚀影响造成的任何金属损失。同样明显的是，冷加工阻碍了疲劳裂纹的萌生并延迟了凹坑到裂纹过渡的开始。