Seol Jae Bok, Ko Won-Seok, Sohn Seok Su, Na Min Young, Chang Hye Jung, Heo Yoon-Uk, Kim Jung Gi, Sung Hyokyung, Li Zhiming, Pereloma Elena, Kim Hyoung Seop
Department of Materials Engineering and Convergence Technology, Center for K-metal & Microscopy, Gyeongsang National University, Jinju, 52828, South Korea.
Department of Materials Science and Engineering, Inha University, Incheon, 22212, South Korea.
Nat Commun. 2022 Nov 9;13(1):6766. doi: 10.1038/s41467-022-34470-8.
Chemical short-range order in disordered solid solutions often emerges with specific heat treatments. Unlike thermally activated ordering, mechanically derived short-range order (MSRO) in a multi-principal-element FeMnCrCo (at%) alloy originates from tensile deformation at 77 K, and its degree/extent can be tailored by adjusting the loading rates under quasistatic conditions. The mechanical response and multi-length-scale characterisation pointed to the minor contribution of MSRO formation to yield strength, mechanical twinning, and deformation-induced displacive transformation. Scanning and high-resolution transmission electron microscopy and the anlaysis of electron diffraction patterns revealed the microstructural features responsible for MSRO and the dependence of the ordering degree/extent on the applied strain rates. Here, we show that underpinned by molecular dynamics, MSRO in the alloys with low stacking-fault energies forms when loaded at 77 K, and these systems that offer different perspectives on the process of strain-induced ordering transition are driven by crystalline lattice defects (dislocations and stacking faults).
无序固溶体中的化学短程有序通常在特定热处理后出现。与热激活有序化不同，多主元FeMnCrCo（原子百分比）合金中的机械衍生短程有序（MSRO）源于77 K下的拉伸变形，其程度可以通过在准静态条件下调整加载速率来定制。力学响应和多尺度表征表明，MSRO的形成对屈服强度、机械孪生和变形诱导位移转变的贡献较小。扫描和高分辨率透射电子显微镜以及电子衍射图谱分析揭示了导致MSRO的微观结构特征以及有序程度对应变率的依赖性。在此，我们表明，在分子动力学的支持下，低堆垛层错能合金在77 K加载时形成MSRO，这些为应变诱导有序转变过程提供不同视角的体系是由晶格缺陷（位错和堆垛层错）驱动的。
