First-principles study of Suzuki segregation at stacking faults in disordered face-centered cubic Co-Ni alloys
First-principles study of Suzuki segregation at stacking faults in disordered face-centered cubic Co-Ni alloys
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DOI：
10.1016/j.actamat.2021.117358
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发表时间：
2021-10
期刊：
影响因子：
9.4
通讯作者：
Dongsheng Wen;M. Titus
中科院分区：
文献类型：
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作者：
Dongsheng Wen;M. Titus
在各种金属材料中观察到的堆垛层错（SF）的形成，如Co基和Ni基合金，影响塑性变形和应变诱导相变。SF形成倾向的一个可能的解释是Suzuki偏析，这是溶质向SF的局部偏析。通过第一性原理计算，我们研究了无序面心立方Co-Ni二元体系中Suzuki分凝的驱动力，并定量预测了由此产生的依赖于温度和组分的层错能（SFE）.利用团簇展开和Monte Carlo模拟相结合的方法预测了无序面心立方Co-Ni二元合金体系中Co向层错区的偏聚。我们发现，在稳定的SFs通过隔离的Co的两个最里面的（111）平面的SFs和预测的偏析随着温度的升高减少的配置和振动效应的援助。我们进一步强调，实验确定的超临界流体是强烈相关的Co偏析和振动自由能的贡献。本文开发的方法可以用来通知合金设计策略，并预测在其他界面问题，如晶界和异质界面偏析。
The formation of stacking faults (SFs) observed in various metallic materials, such as Co-, and Ni-based alloys, influence the plastic deformation and strain-induced phase transformations. One possible explanation for the propensity of SF formation is Suzuki segregation, which is the localized segregation of solute to SFs. Through first-principles calculations, we investigate the driving force of Suzuki segregation in the disordered face-centered cubic Co-Ni binary system and quantitatively predict the resulting temperature- and composition-dependent stacking fault energies (SFEs). We predict the segregation of Co to the stacking fault region in the disordered face-centered cubic Co-Ni binary alloy system utilizing a combination of cluster expansions and Monte Carlo simulations. We find that configurational and vibrational effects aid in stabilizing the SFs through segregation of Co to the two innermost (111) planes in the SFs and predict a reduction of segregation with increasing temperature. We further emphasize that the experimentally determined SFE is strongly related to Co segregation and vibrational free energy contributions. The method developed herein could be leveraged to inform alloy design strategies and predict segregation in other interfacial problems such as grain boundaries and heterointerfaces.