Capture Deformation Twinning in Mg during Shock Compression with Ultrafast Synchrotron X-Ray Diffraction

• Published in: Physical review letters Vol. 123; no. 25; p. 255501
• Main Authors: 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
• Format: Journal Article
• Language: English
• Published: United States 20.12.2019
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.123.255501

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 ⟨112[over ¯]0⟩ and ⟨101[over ¯]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.