摘要
Previous studies have shown that strain-controlled cyclic stability was maintained in bulk Cu samples with highly oriented nanoscale twins. In order to explore the underlying fatigue mechanism, transmission electron microscopy observations under two-beam diffraction condition were utilized to characterize the dislocation configurations in the twin/matrix layers of as-fatigued nanotwinned Cu. It was clarified that the threading dislocations with Burgers vector parallel to twin boundaries are mainly active during fatigue. A three-dimensional stereo projection was re-configured for demonstrating the special structure of dislocations in nanoscale twins.
块体择优取向纳米孪晶Cu在应变疲劳时保持循环稳定.为了研究其本征疲劳机制,本文利用透射电子显微镜在双束条件下研究了纳米孪晶Cu疲劳后孪晶片层内位错形貌特征.结果表明纳米孪晶Cu的疲劳变形多由受限于孪晶片层内部的滑移方向平行于孪晶界面、滑移面倾斜于孪晶界面的单滑移贯穿位错主导.通过三维投影模型重构了贯穿位错在纳米孪晶片层内的空间分布.
基金
supported by the National Basic Research Program of China (2012CB932202)
the National Natural Science Foundation of China (51420105001,51371171 and 51471172)
