Characteristic boundaries associated with three-dimensional twins in hexagonal metals.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32832597.
- Also identified by DOI 10.1126/sciadv.aaz2600 and PMC identifier 7439641.
- Licence recorded as CC BY-NC.
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Abstract
Twinning is a critically important deformation mode in hexagonal close-packed metals. Twins are three-dimensional (3D) domains, whose growth is mediated by the motion of facets bounding the 3D twin domains and influences work hardening in metals. An understanding of twin transformations therefore necessitates that the atomic-scale structure and intrinsic mobilities of facets be known and characterized. The present work addresses the former point by systematically characterizing the boundary structures of 3D <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mrow><mo>{</mo> <mover><mn>1</mn> <mo>¯</mo></mover> <mn>012</mn> <mo>}</mo></mrow> </mrow> </math> twins in magnesium using high-resolution transmission electron microscopy (HRTEM). Eight characteristic facets associated with twin boundaries are reported, five of which have never been experimentally observed before. Further, molecular dynamics simulations suggest that the formation and motion of these facets is associated with the accumulation of twinning dislocations. This work provides insights into understanding the structural character of 3D twins and serves to develop strategies for modulating twin kinetics by modifying twin boundaries, such as solute segregation.