|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Mechanical Behavior at the Nanoscale IV
||Thickness Dependent Strain Rate Sensitivity in Metallic Nanolayers
||Yue Liu, Jennifer Hay, Engang Fu, Xinghang Zhang
|On-Site Speaker (Planned)
The strain-rate sensitivity (SRS) and dislocation activation volume are two inter-related materials properties for understanding thermally activated plastic deformation, such as creep. For face-centered-cubic metals, SRS normally increases with decreasing grain sizes, whereas the opposite holds for body-center-cubic metals. However, these findings are applicable to metals with average grain sizes that are larger than 10nm. The SRS evaluation on sub-10nm feature sizes is important to understand the deformation mechanisms, but is limited by either bulk nanocrystalline metal processing techniques or thermal drift when using conventional nanoindentation on metallic thin films. In this presentation, we present a new nanoindentation method that render hardness insensitive to thermal drift, and the strain rate sensitivity of Cu/X (X=V and Ni) nanolayers. This testing method involves directly measuring contact stiffness and calculating the contact area from the measured stiffness and modulus. The trends of thickness dependent SRS in Cu/V and Cu/Ni nanolayers differ significantly.
||Planned: Supplemental Proceedings volume