|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Pan American Materials Congress: Nanocrystalline and Ultra-fine Grain Materials and Bulk Metallic Glasses
||History-independent Fatigue Response of Polycrystalline Cu with Highly Oriented Nanosclae Twins
||Qingsong Pan, Haofei Zhou, Qiuhong Lu, Huajian Gao, Lei Lu
|On-Site Speaker (Planned)
Nearly 90% of service failures of metallic components and structures are caused by fatigue at a cyclic stress amplitude 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 fatigue, leading to history-dependent and unstable cyclic responses. Here, 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.
||Planned: Stand-alone book in which only your symposium’s papers would appear (indicate title in comments section below)