报告题目 | History-independent cyclic response of nanotwinned Cu |
报告时间 | 2017年11月20日 下午15：30 |
报告地点 | 合肥微尺度物质科学国家实验室一楼科技展厅 |
报告人 | 卢磊研究员 |
报告摘要 | Nearly 90% of service failures of metallic components and structures are caused by fatigue at cyclic stress amplitudes much lower than the tensile strength of the materials involved. A long-standing obstacle to developing better materials has been that metals typically suffer from large, accumulative, irreversible damages in microstructure during cyclic deformation, leading to history-dependent and unstable cyclic responses. In this study, through both experiments and atomistic simulations, we report a history-independent and stable fatigue response in a bulk polycrystalline Cu sample containing highly oriented nanoscale twins under sequences of stepwise increasing/decreasing plastic strain amplitudes. The results demonstrate that this unusual behavior is governed by a type of highly correlated necklace dislocations formed in the nanotwinned metal under cyclic loading. This unique fatigue mechanism is fundamentally distinct from traditional strain-localizing fatigue mechanisms associated with irreversible microstructural damage. |
报告人简介：⑴现在工作单位及职称 ⑵主要研究方向 ⑶学术成就简述（100字以内） 卢磊博士现任中科院金属研究所研究员、博士生导师、国家杰出青年基金获得者中科院特聘研究员、中青年科技创新领军人才。 现任国际著名材料期刊Acta Materialia 和Scripta Materialia编辑，纳米材料国际委员会（International committee of Nanostructured Materials）委员。主要从事金属纳米材料的制备、结构表征、力学性能及变形机制的基础研究。在Nature, Science和Acta Mater.等SCI期刊发表论文百余篇，被SCI他引用8000余次，获国际发明专利3项，50余次国际学术会议特邀报告。获全国优秀百篇博士学位论文奖、SCUPOS寻找“未来科学希望之星”纳米科学领域银奖、中国青年女科学家奖、2014-2016连续获得汤森路透中国“引文桂冠奖--高被引科学家奖”等奖励。 | |
参加者：所有感兴趣的老师和学生 | |
主办单位：微尺度、化学与材料科学学院 | |