|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Mechanical Behavior of Nanostructured Materials
||On the Relationship between the Grain Boundary Character and the Microhardness in Nanocrystalline Ni-W
||Mathieu Lagarde, Niusha Shakibi Nia, Julie Bourgon, Egle Conforto, Patrick Girault, Stéphane Cohendoz, Juan Creus, Xavier Feaugas, Catherine Savall
|On-Site Speaker (Planned)
The microstructural features of nanocrystalline Ni-W 15 at. % alloys with a low content of light elements and different annealing heat treatments has been characterized by several in situ (TEM with heat-holder) and ex-situ (XRD, TEM-ASTAR and SEM-EBSD) techniques and correlated with the micro hardness behaviour. The thermal stability of Ni-W alloys was confirmed for the low annealing temperatures with a very low grain growth and Incoherent Twin Boundaries (ITB) development. This behaviour leads to a significant hardening (inverse Hall Petch relation) arising from twin formation, which hinders the structure deformation because of the increase of the interfaces. Nevertheless, once the thermal stability is overtaken (above 600 – 650 °C), the important grain growth occurs with a decrease in GBs fraction. Classical Hall Petch behaviour is then observed with a more important influence of grain size on the dislocation motion than the twin boundaries effect.
||Planned: Supplemental Proceedings volume