Abstract Co-base superalloys show attractive properties for the strengthening of γ'-Co3(Al,W) precipitates. Directional coarsening of γ' precipitates under external stress forms the rafting morphology, which plays a crucial role in the creep property. The microelastic theory, coupled with the crystal plasticity model, is utilized to study the rafting behavior during the early stage of creep in Co-Al-W superalloys. High W content and large eigenstrain can produce a lower creep strain of early stage, for the subdued plastic deformation in the γ matrix. Driving forces of element redistribution during rafting are compared among the chemical, interfacial and elastic contribution, in which the elastic contribution is dominant in rafting. With the change in creep stress from 197 MPa to 297 MPa, the element redistribution is strengthened, and the rafting is accelerated in Co-10 Al-9 W (at.%) alloy. Elements redistribution in the rafting process widens the γ/γ' interface. In contrast, the width of γ/γ' interface along the rafting direction begins to decrease when the coalescence of γ' precipitates happens. The straight-forward insight on the element diffusion during rafting and the related creep properties guides the composition design and rafting behavior prediction of this novel Co-Al-W superalloy.

中文翻译：

---

γ'相场模拟共基高温合金的漂流和​​蠕变性能

摘要 钴基高温合金在强化 γ'-Co3(Al,W) 析出物方面表现出吸引人的性能。γ'析出物在外应力作用下定向粗化形成筏形形态，这对蠕变性能起着至关重要的作用。微弹性理论与晶体塑性模型相结合，用于研究 Co-Al-W 高温合金蠕变早期阶段的漂流行为。高W含量和大本征应变可以产生较低的早期蠕变应变，用于γ基体的柔和塑性变形。比较了漂流过程中元素重新分布的驱动力在化学贡献、界面贡献和弹性贡献之间，其中弹性贡献在漂流中占主导地位。随着蠕变应力从 197 MPa 到 297 MPa 的变化，单元重新分布得到加强，Co-10 Al-9 W (at.%) 合金加速漂流。漂流过程中的元素重新分布扩大了 γ/γ' 界面。相反，当γ'沉淀物发生聚结时，γ/γ'界面沿漂流方向的宽度开始减小。对漂流过程中元素扩散和相关蠕变特性的直接了解指导了这种新型 Co-Al-W 高温合金的成分设计和漂流行为预测。