报告题目：History-independent cyclic response of nanotwinned Cu

报告人: Prof. L. Lu

Shenyang National Laboratory for Materials Science, Institute of Metal Research,

Chinese Academy of Sciences, Shenyang 110016, P.R. China

时间：2017年12月22日（周五）下午14:30

地点：中科院力学所1号楼344会议室

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：

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、科技部万人计划领军人才。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。