Dislocation cell structures in copper in torsion and tension

✍ Scribed by M. Nabil Bassim; C.D. Liu

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 859 KB
• Volume: 164
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/0921-5093(93)90656-y

✦ Synopsis

A comparative study of the deformation of commercial copper in torsion and in tension was undertaken. Specimens for both tests had the same grain size and underwent the same heat treatment. In tensile specimens, dislocation cell structures were observed in specimens cut in the direction of the applied load while specimens were obtained parallel to the longitudinal axis in torsion. This was followed by transmission electron microscopy examination. It was observed that in tension, the work hardening rate is much higher than in torsion. The dislocation structures in tension are characterized by the formation of sharp subgrain boundaries while in torsion, laminar dislocation structures consisting of paired sheets evolved together with other paired sheets forming checkerboard patterns. These patterns were exhibited up to strains of about 440%. The resistance to bowing out of free dislocation segments in the two cases explains the difference in the work hardening for both tension and torsion.