Insights into plastic deformation mechanisms of austenitic steels by coupling generalized stacking fault energy and semi-discrete variational Peierls-Nabarro model

作     者：Yu Liu Jinglian Du Shunli Shang Ang Zhang Shoumei Xiong Zi-Kui Liu Feng Liu Yu Liu;Jinglian Du;Shunli Shang;Ang Zhang;Shoumei Xiong;Zi-Kui Liu;Feng Liu

作者机构：State Key Laboratory of Solidification Processing Northwestern Polytechnical University Department of Materials Science and Engineering The Pennsylvania State University University Park College of Materials Science and Engineering Chongqing University School of Materials Science and Engineering Tsinghua University Analytical & Testing Center Northwestern Polytechnical University 

出 版 物：《Progress in Natural Science:Materials International》 (自然科学进展·国际材料(英文))

年 卷 期：2023年第33卷第1期

页      面：83-91页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 

基　　金：financially supported by the National Natural Science Foundation of China (Grant No. 52171013, 52130110) the Natural Science Foundation of Chongqing (Grant No. CSTB2022NSCQMSX0369) the Fundamental Research Funds for the Central Universities(Grant No. 3102020QD0412) the “2020–2022 Youth Talent Promotion Project” of China Association for Science and Technology (Grant No. 2020QNRC001) 

主　　题：Austenite Plastic deformation mechanisms Dislocation core structure Generalized stacking fault energy Peierls-Nabarro model 

摘      要：The generalized stacking fault energy(GSFE) is a key parameter to determine the plastic deformation mechanisms of austenitic steels. However, the underlying physics why the GSFE can affect the plastic deformation behaviors remains unclear. In this paper, the plastic deformation mechanisms of austenitic steels with different carbon(C)additions were investigated by coupling the GSFE with the semi-discrete variational Peierls-Nabarro(P–N) model.The internal mechanisms behind the P–N stress and plastic deformation were explained at atomic scale. It is found that the positions and contents of C atoms affect the GSFE of austenite, and thus regulate plastic deformation behaviors of austenitic steels by influencing dislocation core structure. As exemplified that with 4 at.%C in austenite, the intrinsic stacking fault energy increases from-433 to-264 mJ/m2, and the stacking fault width increases to 6.62b from 4.72b of FCC-Fe with b being the Burgers vector. This corresponds to the plastic deformation mechanism dominated by the ε martensitic transformation with the lattice changing from FCC to HCP.With increasing C contents to 8 at.%, the intrinsic stacking fault energy of austenite increases to-9.01 mJ/m2,while the stacking fault width decreases to 6.03b. The plastic deformation tends to proceed via the mechanical twinning mode. The present investigation establishes a solid foundation for clarifying the plastic deformation mechanisms of austenitic steels from the perspective of the dislocation core structure.