Twinnability of hcp metals at the nanoscale

Ya-Fang Guo, Shuang Xu, Xiao-Zhi Tang, Yue-Sheng Wang, Sidney Yip

doi:10.1063/1.4881756

Twinnability of hcp metals at the nanoscale

DOI PDF 被引用文献1件

Ya-Fang Guo

Beijing Jiaotong University 1 Institute of Engineering Mechanics, , Beijing 100044, China
Shuang Xu

Beijing Jiaotong University 1 Institute of Engineering Mechanics, , Beijing 100044, China
Xiao-Zhi Tang

Beijing Jiaotong University 1 Institute of Engineering Mechanics, , Beijing 100044, China
Yue-Sheng Wang

Beijing Jiaotong University 1 Institute of Engineering Mechanics, , Beijing 100044, China
Sidney Yip

Massachusetts Institute of Technology 2 Department of Nuclear Science and Engineering, , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA

抄録

<jats:p>Twinning is generally considered to be the primary deformation mechanism for hexagonal close-packed (hcp) metals due to their limited slip systems. Recent microcompression experiments point to strong size effects indicating that pyramidal slips can dominate in deformation under compression. We present analysis on the twinnability of an ideal hcp single crystal at the nanoscale. A criterion for deformation twinning is derived by considering the elastic lattice-rotation strain, and the result tested against molecular dynamics simulations of magnesium and titanium single crystals. We find ⟨c + a⟩ pyramidal slip dominates the compression deformation at the nanoscale, which is consistent with experimental observations on microcompression. This analysis gives an interpretation of size effects in deformation twinning, at the same time it provides an explanation for the so-called strength differential effect.</jats:p>