Critical Resolved Shear Stresses of Two Slip Systems in Bismuth Single Crystals

Abstract

The temperature and strain rate dependences of the critical resolved shear stress of bismuth single crystal are investigated by compression tests for two slip systems, (111) <10> and {001} <0>, over the temperature range from 77 K to 538 K. From the results the activation energy U0 and the activation volume of dislocation motion for each slip system are determined. They are 0.1 eV and 2×10-19 cm3 for the (111) <10> slip system, 0.4 eV and 0.06×10-19 cm3 for the {001} <0> slip system, respectively. It is concluded that for the (111) <10> slip system the main obstacle to moving dislocations is the forest dislocation, and for the {001} <0> slip system the Peierls potential controls the slip mechanism.