Hardening of pure metals by high-pressure torsion: A physically based model employing volume-averaged defect evolutions
Abstract
A physically based model to predict the increment of hardness and grain refinement of pure metals due to severe plastic deformation by high-pressure torsion (HPT) is proposed. The model incorporates volume-averaged thermally activated dislocation annihilation and grain boundary formation. Strengthening is caused by dislocations in the grain and by grain boundaries. The model is tested against a database containing all available reliable data on HPT-processed pure metals. It is shown that the model accurately predicts hardening and grain size of the pure metals, irrespective of crystal structure (face-centred cubic, body-centred cubic and hexagonal close packed). Measured dislocation densities also show good correlation with predictions. The influence of stacking fault energy on hardening is very weak (of the order of -0.03 GPa per 100 J mol-1).
- Publication:
-
Acta Materialia
- Pub Date:
- January 2013
- DOI:
- 10.1016/j.actamat.2012.09.048
- Bibcode:
- 2013AcMat..61..183S
- Keywords:
-
- Severe Plastic Deformation (SPD);
- Dislocations;
- High-pressure torsion;
- Hardness;
- Grain size