Abstract
Deformation twinning in pure aluminum has been considered to be a unique property of nanostructured aluminum. A lingering mystery is whether deformation twinning occurs in coarse-grained or single-crystal aluminum at scales beyond nanotwins. Here, we present the first experimental demonstration of macrodeformation twins in single-crystal aluminum formed under an ultrahigh strain rate () and large shear strain (200%) via dynamic equal channel angular pressing. Large-scale molecular dynamics simulations suggest that the frustration of subsonic dislocation motion leads to transonic deformation twinning. Deformation twinning is rooted in the rate dependences of dislocation motion and twinning, which are coupled, complementary processes during severe plastic deformation under ultrahigh strain rates.
- Received 15 October 2015
DOI:https://doi.org/10.1103/PhysRevLett.116.075501
© 2016 American Physical Society
Physics Subject Headings (PhySH)
Viewpoint
Unexpected Twins
Published 17 February 2016
Aluminum crystals can respond to strain by twinning—a finding that challenges conventional conceptions of material deformation.
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