Twinning-like lattice reorientation without a crystallographic twinning plane

• Published in: Nature communications Vol. 5; no. 1; p. 3297
• Main Authors: Liu, Bo-Yu, Wang, Jian, Li, Bin, Lu, Lu, Zhang, Xi-Yan, Shan, Zhi-Wei, Li, Ju, Jia, Chun-Lin, Sun, Jun, Ma, Evan
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.02.2014; Nature Publishing Group; Nature Pub. Group
• Subjects: 639/301; Humanities and Social Sciences; MATERIALS SCIENCE; multidisciplinary; NANOSCIENCE AND NANOTECHNOLOGY; Science; Science & Technology - Other Topics; Science (multidisciplinary)
• DOI: 10.1038/ncomms4297
• ISSN: 2041-1723

Twinning on the plane is a common mode of plastic deformation for hexagonal-close-packed metals. Here we report, by monitoring the deformation of submicron-sized single-crystal magnesium compressed normal to its prismatic plane with transmission electron microscopy, the reorientation of the parent lattice to a ‘twin’ lattice, producing an orientational relationship akin to that of the conventional twinning, but without a crystallographic mirror plane, and giving plastic strain that is not simple shear. Aberration-corrected transmission electron microscopy observations reveal that the boundary between the parent lattice and the ‘twin’ lattice is composed predominantly of semicoherent basal/prismatic interfaces instead of the twinning plane. The migration of this boundary is dominated by the movement of these interfaces undergoing basal/prismatic transformation via local rearrangements of atoms. This newly discovered deformation mode by boundary motion mimics conventional deformation twinning but is distinct from the latter and, as such, broadens the known mechanisms of plasticity. Deformation twinning and dislocations are known to govern the plastic behaviour of metals at room temperature. Here the authors demonstrate a new deformation mechanism in single-crystal magnesium characterized by twin-like crystal reorientation and special interfaces.