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.

在这项研究中，使用晶体弹-粘塑性有限元分析（CEV-FEA）研究了热电厂运行期间发生的铁素体/马氏体9Cr-1Mo（T91级）钢锅炉管的蠕变变形。T91等级的材料性能和蠕变行为是通过不同规模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。通过CEV-FEA还模拟了具有多晶T91级多晶取向组合的晶粒的三重结，以研究蠕变变形过程中应力集中的演变。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接收到的锅炉管的蠕变寿命的评估，而对材料量和测试时间的要求最低。