The interplay between solute atoms and vacancy clusters in magnesium alloys
The interplay between solute atoms and vacancy clusters in magnesium alloys
复制标题
镁合金中溶质原子与空位簇之间的相互作用
DOI：
10.1016/j.actamat.2023.118805
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发表时间：
2023
期刊：
影响因子：
9.4
通讯作者：
Falk Michael L.
中科院分区：
文献类型：
--
作者：
Yi Peng;Sasaki Taisuke T.;Eswarappa Prameela Suhas;Weihs Timothy P.;Falk Michael L.
原子尺度的计算表明，在存在空位团簇的镁合金中，应力效应和化学结合都有助于溶质的重新分配，从而导致溶质在热力学驱动下的偏析。随着空位簇大小的增加，化学结合相对于应力变得更加重要。这些溶质-空位相互作用也会影响空位和空位团簇在固溶体中的扩散率。模拟结果表明，溶质原子加速了单空位扩散，但减缓了空位团簇的扩散。因此，溶质原子促进了聚类并稳定了产生的空位团簇，增加了它们促进溶质偏析的潜力，并在沉淀过程中充当了异质成核的位置。同时变形和时效的Mg-Al合金中溶质偏析的实验观察为这一机制提供了支持。
Atomic-scale calculations indicate that both stress effects and chemical binding contribute to the redistribution of solute in the presence of vacancy clusters in magnesium alloys, leading to solute segregation driven by thermodynamics. As the size of the vacancy cluster increases, chemical binding becomes more important relative to stress. These solute–vacancy interactions also impact the diffusivity of vacancies and vacancy clusters in a solid solution. Simulations show that solute atoms accelerate mono-vacancy diffusion but decelerate the diffusion of vacancy clusters. As a result, solute atoms facilitate clustering and stabilize the resulting vacancy clusters, increasing their potential to promote solute segregation and to serve as heterogeneous nucleation sites during precipitation. Experimental observation of solute segregation in simultaneously deformed and aged Mg–Al alloys provides support for this mechanism.