Here, the Cottrell–Stokes ratio in a microstructurally-stable Cu-3Ta (at.%) nanocrystalline alloy is examined from the standpoint of changes in deformation mechanisms. Toward this, uniaxial compression experiments were performed in the temperature range of 113 K – 273 K. The Cottrell-Stokes ratio at the lowest temperature tested was ~1.3, and the material exhibited a very low strain-rate sensitivity at cryogenic-temperatures. Transmission electron microscopy (TEM) characterization showed negligible average grain size coarsening and a transition in the deformation mechanism toward athermal activation processes such as twinning with the reduction in the testing temperature.
- Transmission electron microscopy
- Zener-Hollomon parameter
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics