A systematic analysis of phase stability in refractory high entropy alloys utilizing linear and non-linear cluster expansion models
A systematic analysis of phase stability in refractory high entropy alloys utilizing linear and non-linear cluster expansion models
复制标题
利用线性和非线性簇扩展模型系统分析难熔高熵合金的相稳定性
DOI：
10.1016/j.actamat.2021.117269
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发表时间：
2021
期刊：
影响因子：
9.4
通讯作者：
Samanta, Amit
中科院分区：
文献类型：
--
作者：
Nataraj, Chiraag;Borda, Edgar Josué;van de Walle, Axel;Samanta, Amit
采用第一性原理计算方法研究了三种关键的难熔高熵合金（NbTiVZr、HfNbTaTiZr和AlHfNbTaTiZr）的相偏析行为。几种线性和非线性的方法被用来生成代理模型的三个关键的耐火高熵合金（NbTiVZr，HfNbTaTiZr，和AlHfNbTaTiZr）通过集群扩展形式主义。每个生成的模型的特点进行了探索，并比较回归方法。最后，这些替代模型被用来生成Monte Carlo轨迹，以探索相分离和以前记录的机械退化在这些material.Phase偏析和金属间相记录在实验文献中再现在所有三个高熵合金之间的联系。NbTiVZr在较低温度（250 K）下形成钒和锆团簇，到1000 K时，这些团簇分散到单相基体中。HfNbTaTiZr在较低温度（250 K）下形成HfZr、NbTa和可能的TiZr金属间相。与这里研究的其他HEAs不同，HfNbTaTiZr在固态下直到3500 K左右才失去短程有序，这高于其熔化温度。AlHfNbTaTiZr在较低温度（250 K）下形成NbTa和AlHfTiZr相，这在较高温度（1000 K）下没有观察到。
The phase segregation behavior of three key refractory high entropy alloys (NbTiVZr, HfNbTaTiZr, and AlHfNbTaTiZr) is studied using first-principles calculations. Several linear and non-linear methods are utilized to generate surrogate models for three key refractory high entropy alloys (NbTiVZr, HfNbTaTiZr, and AlHfNbTaTiZr) via the cluster expansion formalism. The characteristics of each of the generated models is explored and the regression methods are compared. Finally, these surrogate models are utilized to generate Monte Carlo trajectories in order to explore the link between phase segregation and previously documented mechanical degradation in these materials.Phase segregation and intermetallic phases documented in the experimental literature are reproduced in all three high entropy alloys. NbTiVZr forms vanadium and zirconium clusters at lower temperatures (250 K) which disperse into the single-phase matrix by 1000 K. HfNbTaTiZr forms HfZr, NbTa, and possibly TiZr intermetallic phases at lower temperatures (250 K). Unlike the other HEAs studied here, HfNbTaTiZr does not lose short-range ordering in the solid state until around 3500 K, which is above its melting temperature. AlHfNbTaTiZr forms NbTa and AlHfTiZr phases at lower temperatures (250 K), which are not observed at higher temperatures (1000 K).