|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Deformation and Transitions at Interfaces
||Stresses in Reverse-deformed Single Crystal Cu: Quantitative Tests of the Composite Model
||Lyle Levine, Thien Phan, I-Fang Lee, Ruqing Xu, Yaakov Idell, Michael E Kassner
|On-Site Speaker (Planned)
In 2011, we used depth-resolved, sub-micrometer synchrotron X-ray diffraction to measure stresses within numerous individual dislocation cell interiors and cell walls in heavily-deformed Cu. Separated, asymmetric stress distributions were found, demonstrating that the evolving dislocation wall structures develop strong dipolar stress fields. These findings proved that the fundamental mechanisms of the Mughrabi composite model for work hardening were correct, but couldn’t address the more important question of whether the composite model could explain mechanical behaviors such as the Bauschinger effect. We present depth-resolved, sub-micrometer diffraction measurements from monotonic and slightly reverse-loaded deformed Cu. The measurements show a substantial decrease in the long-range stresses with only a slight reversal in the plastic strain. These results demonstrate that the composite model is not a viable explanation for the Bauschinger effect in deformed Cu, and that substantial dislocation-wall “unraveling,” as considered in the Orowan–Sleeswyk model of work hardening, occurs during reverse loading.