Temperature dependence of the flow stress and the strain rate sensitivity at the transition from the Peierls mechanism to pinning by localized obstacles

¹ Institute of Crystallography, Russian Academy of Sciences, Leninskii Prospect 59, Moscow 117333, Russia
² Max Planck Institute of Microstructure Physics, Weinberg 2, Halle/Saale 06120, Germany

Corresponding author: petukhov@ns.crys.ras.ru

Received: 19 June 1999
Revised: 22 July 1999
Accepted: 5 October 1999
Published online: 15 February 2000

Abstract

Barriers of very different character such as localized obstacles and the extended Peierls- Nabarro relief may control the dislocation motion in crystals in different stress and temperature ranges. The great difference in the microscopic parameters characterizing these two mechanisms, e.g., in the activation volumes, manifests itself even on the macroscopic scale as a strong change of the plastic properties in a rather narrow transition range of the temperature. A theory describing the temperature dependence of the flow stress and the strain rate sensitivity near the transition has been developed and compared with experimental data on the plastic deformation of cubic ZrO₂ single crystals in a soft orientation.