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Advances in Materials Science and Engineering
Volume 2018, Article ID 4254156, 6 pages
Research Article

Transition of Dislocation Structures in Severe Plastic Deformation and Its Effect on Dissolution in Dislocation Etchant

1Department of Mechanical Engineering, Doshisha University, Kyoto, Japan
2Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, Iran
3Graduate School of Science and Engineering, Doshisha University, Kyoto, Japan

Correspondence should be addressed to Muhammad Rifai;

Received 27 September 2017; Revised 11 December 2017; Accepted 18 December 2017; Published 30 January 2018

Academic Editor: Alicia E. Ares

Copyright © 2018 Muhammad Rifai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Transition of dislocation structures in ultrafine-grained copper processed by simple shear extrusion (SSE) and its effects on dissolution were manifested by simple immersion tests using a modified Livingston dislocation etchant, which attacks dislocations and grain boundaries selectively. The SSE process increased the internal strain evaluated by X-ray line broadening analysis until eight passes but decreased it with further extrusion until twelve passes. The weight loss in the immersion tests reflected the variation in the internal strain: namely, it increased until eight passes and then decreased with further extrusion to twelve passes. Taking our previous report on microstructural observation into account, it is suggested that variation in the internal strain is caused by both the variation in dislocation density and structural change of grain boundaries from equilibrium to nonequilibrium states or vice versa. Decreased dislocation density and structural change back to equilibrium state of grain boundaries in very high strain range by possibly dynamic recovery as pointed out by Dalla Torre were validated by X-ray and dissolution in the modified Livingston etchant in addition to the direct observation by TEM reported in our former report.