Anomalous yielding in alloys at low temperatures

Abstract
The available data on the temperature dependence of the critical resolved shear stress τ of aluminium single crystals containing 0·6 to 9·0 at.% magnesium in the range 1·6 to 135 K are examined within the framework of the kink-pair model of solid-solution hardening. The anomalous behaviour at low temperatures, i.e. the reversal of the sign of dτ/dT below a critical temperature T 0 is considered to be a consequence of structural changes in slip bands as T→0K, which necessitates the introduction of a stress-concentration factor f(T) = exp[1-(T/T 0)α] into the equations of plastic flow. The constant α, like the critical temperature T 0, is specific to the material.