ABSTRACT In this study, the creep deformation of ferritic/martensitic 9Cr-1Mo (Grade T91) steel boiler tubes that occurs during the operation of thermal power plants is studied using crystal elasto-viscoplasticity finite element analysis (CEV-FEA). The material properties and creep behaviour of Grade T91 were obtained through experimentation and computational analysis at different scales, e.g., molecular dynamics simulation, scanning electron microscopy, small punch (SP) tests. A triple junction of grains with various combinations of crystallographic orientations of polycrystalline Grade T91 was also simulated by CEV-FEA to investigate the stress concentration evolution during creep deformation. The stress concentration at the triple junction was then used as an input for the creep cavitation model, i.e., as the representative stress driving creep cavitation. The combination of CEV-FEA and SP test experiments can improve the evaluation of creep lifetime for as-received boiler tubes with minimum requirements for the amount of material and testing time.

中文翻译：

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通过小冲头蠕变试验和分层多尺度分析预测 9Cr-1Mo（T91 级）钢的蠕变寿命

摘要 在这项研究中，铁素体/马氏体 9Cr-1Mo（T91 级）钢锅炉管在火力发电厂运行期间发生的蠕变变形使用晶体弹粘塑性有限元分析 (CEV-FEA) 进行了研究。T91 级的材料性能和蠕变行为是通过不同尺度的实验和计算分析获得的，例如分子动力学模拟、扫描电子显微镜、小冲头 (SP) 测试。CEV-FEA 还模拟了具有不同结晶取向的多晶 T91 级晶粒的三重结，以研究蠕变变形过程中的应力集中演变。然后将三重结处的应力集中用作蠕变空化模型的输入，即，作为代表应力驱动蠕变空化。CEV-FEA 和 SP 测试实验的结合可以提高对原样锅炉管蠕变寿命的评估，同时对材料量和测试时间的要求最低。