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Dislocation Mobility in the {11 2 2} 〈11 2 3〉 Slip System of Zinc Single Crystals
Author(s) -
Lavrentev F. F.,
Salita O. P.,
Vladimirova V. L.
Publication year - 1968
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.19680290206
Subject(s) - critical resolved shear stress , dislocation , slip (aerodynamics) , shear stress , materials science , condensed matter physics , shear (geology) , dislocation creep , zinc , atmospheric temperature range , crystallography , composite material , thermodynamics , viscosity , chemistry , shear rate , metallurgy , physics
Abstract Results are presented of measurements of the stress dependence of screw dislocation velocities in the {11 2 2} 〈11 2 3〉 slip system (pyramidal slip) of zinc single crystals. The investigations have been carried out on zinc single crystals of 99.999% purity at room temperature. The dislocation mobility has been studied within a wide range of velocities and shear stresses below and above the critical resolved shear stress. When the shear stress τ changed from 20 to 4000 p/mm 2 the dislocation velocity v varied from 10 −3 to 10 4 cm/s. A strong dependence of v on τ is observed in the stress range 20 to 100 p/mm 2 , which can be described by an exponential and the dislocation mobility is determined by a thermally activated mechanism. A weak linear dependence of v on τ is observed at shear stresses greatly exceeding the critical shear stress (300 to 4000 p/mm 2 ). These results are explained in terms of a phonon viscosity mechanism. The measured drag constant is of the same order of magnitude as that calculated for the mechanism of phonon viscosity.