As the operating temperature of jet turbine engines increase, creep becomes the life-limiting property for turbine disks and blades. At intermediate temperatures, around 600–800 °C, microtwinning contributes significantly to creep strain in these alloys. Therefore, understanding how microtwins form and grow is critical to improving the creep life of future Ni-base superalloy components. In addition, exploring the effect of different alloying elements, such as Nb and Ta, on the formation of microtwins is critical for future alloy development. Several mechanisms of microtwinning have been proposed among which the Kolbe mechanism, based on thermally activated reordering, is believed to be dominant. In this work we employ atomistic simulation to investigate the effects of Nb solutes on the Kolbe mechanism. The simulation demonstrates that Nb atoms significantly slow down the reordering processes, explaining the experimentally observed improvement in the creep resistance.

中文翻译：

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Nb 固溶体对镍基高温合金微孪晶 Kolbe 机理的影响


随着喷气涡轮发动机的工作温度升高，蠕变成为涡轮盘和叶片的寿命限制特性。在中间温度（大约 600–800 °C）下，微孪晶对这些合金的蠕变应变有显着贡献。因此，了解微孪晶如何形成和生长对于提高未来镍基高温合金部件的蠕变寿命至关重要。此外，探索不同合金元素（例如 Nb 和 Ta）对微孪晶形成的影响对于未来合金的开发至关重要。已经提出了几种微孪晶机制，其中基于热激活重排序的科尔贝机制被认为是主导。在这项工作中，我们采用原子模拟来研究 Nb 溶质对 Kolbe 机制的影响。模拟表明，铌原子显着减缓了重排序过程，解释了实验观察到的抗蠕变性的改善。