Geometrically necessary dislocations induced size effect in the torsional stress relaxation behavior of thin metallic wires

Published on Dec 1, 2019in Scripta Materialia5.079
· DOI :10.1016/J.SCRIPTAMAT.2019.08.002
Song Guo10
Estimated H-index: 10
(HUST: Huazhong University of Science and Technology),
Yuming He23
Estimated H-index: 23
(HUST: Huazhong University of Science and Technology)
+ 3 AuthorsShihao Han2
Estimated H-index: 2
(HUST: Huazhong University of Science and Technology)
Source
Abstract
Abstract Torsional stress relaxation experiments on thin copper wires are performed. A size effect is observed. That is a faster relaxation deformation arises in a thinner wire. As the wire diameter increases, the activation volume increases but the strain rate sensitivity decreases. A greater effect of geometrically necessary dislocations on the relaxation deformation accounts for the size effect. In a thinner wire, geometrically necessary dislocations undergo fewer obstacles to reach the wire center and then neutralize, causing a more rapid evolution of mobile dislocations.
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