Twinning pathways in Fe and Fe-Cr alloys from first-principles theory
Twinning pathways in Fe and Fe-Cr alloys from first-principles theory
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根据第一性原理理论研究 Fe 和 Fe-Cr 合金的孪晶路径
DOI：
10.1016/j.actamat.2021.117094
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发表时间：
2021
期刊：
影响因子：
9.4
通讯作者：
Vitos Levente
中科院分区：
文献类型：
--
作者：
Wang Ci;Schonecker Stephan;Li Wei;Yang Yaochun;Hu Qing-Miao;Vitos Levente
利用密度泛函理论，计算了体心立方铁磁合金和Cr含量≤ 0.5的Fe-Cr合金中{1 1 <$2}< 1 <$11>孪晶系统的广义层错能.我们采用反射和等腰孪晶途径，并揭示了GSFE的磁有序效应的对比FM结果的磁无序顺磁（PM）状态。结果表明，在该双星系统中，等腰孪晶界组态是能量优先的。长程磁序的损失降低了GSFE的振幅，但增加了孪晶界迁移（TBM）的能量，无论Cr含量。在FM和PM状态下，孪晶晶界形成（TBF）能和TBM能与Cr含量呈非线性关系，Cr对这些性质的影响主要取决于磁性状态。我们讨论了我们的结果方面的稳定孪晶界结构和变形孪晶实验观察到的均匀Fe-50重量%铬合金的温度略高于磁有序温度。
Using density-functional theory, we determine the generalized stacking fault energy (GSFE) for the {1 1¯ 2}< 1¯ 11> twinning system in ferromagnetic (FM) body-centered cubic Fe and Fe–Cr alloys with molar fraction of Cr≤ 0.5. We adopt both reflection and isosceles twinning pathways and reveal the magnetic ordering effects on the GSFE by contrasting the FM results to those obtained for the magnetically disordered paramagnetic (PM) state. The results show that the isosceles twin boundary configuration is energetically preferred in this binary. The loss of long-range magnetic order lowers the GSFE amplitude but increases the twin boundary migration (TBM) energy regardless of the Cr content. The twin boundary formation (TBF) energy and the TBM energy show non-linear dependences on Cr content in the FM and PM states, and the effect of Cr on these properties critically depends on the magnetic state. We discuss our results in regard to the stable twin boundary structure and deformation twinning experimentally observed in homogeneous Fe-50 wt.% Cr alloy up to temperatures slightly above the magnetic ordering temperature.