|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Thermal and Mechanical Stability of Nanocrystalline Materials
||Grain Boundary Stability Governs Hardening and Softening in Extremely-fine Nano-grained Metals
||Jian Hu, Yinong Shi, Xavior Sauvage, Gang Sha, K. Lu
|On-Site Speaker (Planned)
Conventional metals become harder with decreasing grain sizes, following the classical Hall-Petch relationship. However, this relationship fails and softening occurs at some grain size in the nanometer regime for some of alloys. In this study, we discovered that plastic deformation mechanism of extremely-fine nano-grained metals and their hardness are adjustable by tailoring grain boundary (GB) stability. The electro-deposited nano-grained Ni-Mo samples become softened for grain sizes below 10 nm due to GB-mediated processes. With GB stabilization through relaxation and Mo segregation, ultrahigh hardness is achieved in the nano-grained samples with a plastic deformation mechanism dominated by generation of extended partial dislocations. Hardness of nano-grained materials depends not only on grain size but also upon GB stability. Grain boundary stability provides an alternative dimension, in addition to grain size, for producing novel nano-grained metals with extraordinary properties.
||Planned: Supplemental Proceedings volume