ABSTRACT Primary creep regeneration (PCR), i.e. re-occurrence of the primary creep stage for a material loaded under stress-varying creep conditions, is an important consideration for the design and assessment of high-temperature components operating under cyclic loading conditions. This study reviews observations from a comprehensive creep experiment program aiming to understand the PCR behaviour of two high-temperature steels with very different metallurgical-microstructural characteristics at their respective application temperatures; namely 316H austenitic stainless steel at 650°C and a 10%Cr martensitic steel at 600°C. The program included twelve (stress-varying) creep tests for each steel which were systematically designed to characterise the PCR and anelastic recovery response of the steels under various loading scenarios. The experimental observations showed that the PCR behaviour of both steels is similarly sensitive to the parameters of the loading profile and PCR is more pronounced for e.g. larger reverse-loading magnitudes or longer reverse-loading durations. Detailed analysis however showed that the early PCR response is different for the two steels and the 10%Cr steel showed significantly higher creep rates immediately after a stress-transient. Similarly, it was found that although the anelastic recovery response of both steels shares similar sensitivity to the parameters of the prior-loading profile, the extent of anelastic recovery is less significant for the 316H steel. The observed PCR and anelastic recovery behaviour of the two steels have been interpreted based on their dislocation-structure and microstructural features.

中文翻译：

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316H奥氏体钢和10%Cr马氏体钢一次蠕变再生和弹性回复行为的比较

摘要 初级蠕变再生 (PCR)，即在应力变化蠕变条件下加载的材料的初级蠕变阶段的再次发生，是设计和评估在循环加载条件下运行的高温部件的重要考虑因素。本研究回顾了综合蠕变实验计划的观察结果，旨在了解两种高温钢在其各自的应用温度下具有截然不同的冶金微观结构特征的 PCR 行为；即 650°C 下的 316H 奥氏体不锈钢和 600°C 下的 10%Cr 马氏体钢。该计划包括对每种钢进行 12 次（随应力变化的）蠕变测试，这些测试被系统地设计为表征钢在各种负载情况下的 PCR 和弹性恢复响应。实验观察表明，两种钢的 PCR 行为对加载曲线的参数同样敏感，并且 PCR 对于例如更大的反向加载幅度或更长的反向加载持续时间更为明显。然而，详细分析表明，两种钢的早期 PCR 响应不同，10% Cr 钢在应力瞬变后立即显示出显着更高的蠕变速率。类似地，发现虽然两种钢的弹性恢复响应对先前加载曲线的参数具有相似的敏感性，但 316H 钢的弹性恢复程度不那么显着。观察到的两种钢的 PCR 和弹性恢复行为已经根据它们的位错结构和显微结构特征进行了解释。