In the absence of protective scales, nickel-base superalloys have an extremely limited hot corrosion incubation period before increased rates of attack are experienced. This paper reports on the nickel-base superalloys: CMSX-4, CM247LC DS and IN6203DS subjected to 550 °C hot corrosion exposures of durations ranging from 0 to 800 h, during which none of the superalloys developed a fully protective scale. The aim of the research was to identify the incubation period of each superalloy and this was achieved by means of surface roughness evaluations. A metrology exercise was performed on the cross section of test specimens which produced Cartesian data points which were subsequently converted to Ra and Rz data. Statistical analysis of the results suggested the incubation period lasted approximately 400, 500 and 200 h, respectively, for each superalloy. It was concluded that refractory metal phases within the microstructure were associated with the relatively short IN6203DS incubation period. This paper demonstrates that monitoring the changes in surface roughness provides a plausible method to identify the transition from incubation to propagation when studying 550 °C hot corrosion attack.

中文翻译：

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确定镍基高温合金热腐蚀的潜伏期的表面粗糙度演变：CMSX-4、CM247LC DS 和 IN6203DS 在 550 °C

在没有保护层的情况下，镍基高温合金在经历增加的侵蚀速率之前的热腐蚀潜伏期极其有限。本文报告了镍基高温合金：CMSX-4、CM247LC DS 和 IN6203DS，它们经受了 550 °C 的热腐蚀暴露，持续时间为 0 到 800 小时，在此期间，没有一种高温合金形成完全保护层。研究的目的是确定每种高温合金的潜伏期，这是通过表面粗糙度评估来实现的。对测试样品的横截面进行了计量练习，产生了笛卡尔数据点，随后将其转换为 Ra 和 Rz 数据。结果的统计分析表明，每种高温合金的潜伏期分别持续了大约 400、500 和 200 小时。得出的结论是，微观结构内的难熔金属相与相对较短的 IN6203DS 潜伏期有关。本文表明，在研究 550 °C 热腐蚀侵蚀时，监测表面粗糙度的变化提供了一种可行的方法来确定从孵化到传播的转变。