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Chen, S; Li, Y X; Zhang, N B; Huang, J W; Hou, H M; Ye, S J; Zhong, T; Zeng, X L; Fan, D; Lu, L; Wang, L; Sun, T; Fezzaa, K; Zhang, Y Y; Tang, M X; Luo, S N
Physical review letters, 2019-Dec-20, Letnik: 123, Številka: 25Journal Article
Deformation twinning plays a vital role in accommodating plastic deformation of hexagonal-close-packed (hcp) metals, but its mechanisms are still unsettled under high strain rate shock compression. Here we investigate deformation twinning in shock-compressed Mg as a typical hcp metal with in situ, ultrafast synchrotron x-ray diffraction. Extension twinning occurs upon shock compression along ⟨112over ¯0⟩ and ⟨101over ¯0⟩, but only upon release for loading along ⟨0001⟩. Such deformation mechanisms are a result of the polarity of deformation twinning, which depends on directionality and relative magnitude of resolved shear stress and may be common for Mg and its alloys in a wide range of strain rates.
