Description:
<jats:title>Abstract</jats:title><jats:p>The parameter α = <jats:italic>H/kT</jats:italic><jats:sub>m</jats:sub> characterizes the resistance of a crystal lattice to dislocation motion. For crystals with a covalent component of the interatomic bond the parameter α increases with the degree of the interatomic bond orientation. At high temperatures α determines the value of the critical shear stress and the temperature <jats:italic>t</jats:italic>* at which a sharp change of the temperature dependence of the critical shear stress begins. It is shown that <jats:italic>t</jats:italic>* = <jats:styled-content>\documentclass{article}\pagestyle{empty}\begin{document}$\sqrt {\alpha /} \sqrt {3\,c} $\end{document}<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/tex2gif-ueqn-1.gif" xlink:title="equation image" /></jats:styled-content>, where <jats:italic>c</jats:italic> characterizes the slope of the curve τ<jats:sub>cr</jats:sub> = <jats:italic>f</jats:italic>(<jats:italic>T</jats:italic>) at the temperature <jats:italic>t</jats:italic>*. Passage of the temperature <jats:italic>t</jats:italic>* is accompanied by a change in the mechanism of plastic deformation. The correlation of strength and plastic properties with the degree of the interatomic bond orientation is discussed.</jats:p>