个人信息Personal Information
学历：博士研究生毕业
学位：工学博士学位
性别：男
学科：力学. 航空宇航科学与技术. 材料科学与工程. 机械工程. 冶金工程. 先进制造. 航空工程. 材料工程. 冶金工程. 机械工程. 固体力学
多尺度力学，宏微观力学，梯度结构材料，界面力学，固体本构关系，应变梯度理论，晶体塑性有限元，离散位错动力学，分子动力学，高熵合金，大数据与机器学习，材料基因，极端力学，高性能材料，材料的增强与增韧
2022-07-02 硕士生吴丹论文“Interactions between screw dislocation and twin boundary in high-entropy alloy: A molecular dynamic study”在Computational Materials Science在线发表
发布时间：2022-07-02
Highlights:
•Only transmission was found during the interaction process between a screw dislocation and twin boundary in CoNiCrFeMn HEA and pure Ni.
•Screw dislocation constricts asynchronously at the twin boundary in HEA when it transmits through the twin boundary.
•Simultaneous constriction of Shockley partials at the twin boundary is unnecessary for the screw dislocations to pass through the twin boundary.
•Negative stacking fault energy and lattice friction play an important role in the interaction process.
Abstract
The interaction between dislocations and twin boundaries plays an important role in the plastic deformation of high-entropy alloys (HEAs), in which deformation twinning mechanisms are highly active. However, research concerning the twinning-induced strengthening in HEAs is lacking, especially atomistic studies. Therefore, molecular dynamics (MD) simulations are performed to elucidate the interaction mechanisms between the screw dislocation and the coherent twin boundary in the CoNiCrFeMn HEA and pure Ni. Dislocation transmission across the twin boundary is observed as the only mode in the CoNiCrFeMn HEA and pure Ni. However, the Shockley partial dislocations cannot simultaneously constrict on the twin boundary in the CoNiCrFeMn HEA because of the nanoscale segment detrapping mechanism related to the statistical fluctuation of chemical ordering, different from that in pure Ni. To quantify the interaction mechanism, generalized stacking fault energies and lattice friction are considered for predicting the interaction mode in the CoNiCrFeMn HEA. A new material parameter that considers the negative stacking fault energy and large lattice friction stress is proposed for the CoNiCrFeMn HEA.
Link
https://doi.org/10.1016/j.commatsci.2022.111626