Asymmetrical behaviour of “60°” dislocation glide in indium antimonide

By a special technique the motion of α- or β-type dislocations is selected during the plastic deformation of InSb. The experimental results show a strong difference between the two cases; one being “harder” than the other. In both the cases, the dislocation motion is strongly thermally activated below T ≈︁ 280 °C. An analysis of the results shows that it is possible to deduce the activation parameters of the glide from measurements of the relaxation volume performed at the lower yield point, in spite of a strong work-hardening. The activation free enthalpy can therefore be deduced for each α- or β-case: one finds 0.6 and 1.1 eV, respectively. These two different values indicate that α- and β-dislocations do not possess the same velocity, at least below 280 °C.