Plasticity and thermal recovery of thin copper wires in torsion

Abstract

Experiments in small-scale plasticity usually focus on small-sized samples. However, studying thin wires with lengths up to metres in torsion has the advantage of giving extremely high strain resolution and reversal of the loading direction. In this way, we explore the early stage of plasticity. Microstrain plastic deformation, dislocation creep and the Bauschinger effects are easily observed. The onset of irreversible deformation was observed and associated with a few dislocations in the largest grains throughout the wire. Easy plastic deformation on reversal of the loading direction was observed following this initial plastic deformation but not before.

Keywords:

• small-scale plasticity
• torsion
• creep
• Bauschinger effects
• copper

Acknowledgements

We are grateful to G. Gannaway for the construction of the equipment required for the torsion tests and Prof W.P. Gillin for the RTA. Dong Dong gratefully acknowledges the provision of a China Scholarship Council award.