Twin and dislocation mechanisms in tensile W single crystal with temperature change: a molecular dynamics study
YX Feng and JX Shang and SJ Qin and GH Lu and Y Chen, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 20, 17727-17738 (2018).
Molecular dynamics simulations are performed to investigate the orientation and temperature dependence of tensile response in single crystal W. It is found that W single crystal exhibits distinct temperature-dependent deformation behaviors along different orientations. With increasing temperature, the yield strain in the 001 orientation increases, while those in 110 and 111 orientations first increase and then decrease. The tensile deformations along orientations close to 001 are found to be dominated by twinning; the nucleation and growth of twins are accomplished through the nucleation and glide of ?111 partial dislocations on 112 planes. In contrast, the deformations along orientations close to 110 and 111 are found to be dominated by the slip of 1/2111 full dislocations, which move in a stay-and-go fashion. Moreover, intermediate deformation behaviors, which may become unstable at high temperatures, are observed for some intervening orientations. The distinct deformation behaviors of W along different orientations are rationalized based on the twinning-antitwinning asymmetry of ?111 partial dislocations on 112 planes.
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