Solid-Solution Hardening in Concentrated Solutions

The stress required to move a dislocation in a solid-solution alloy is considered. The analysis is based on a model which is particularly applicable to concentrated solid solutions. The energy fluctuations a dislocation segment encounters on moving through a crystal due to random composition fluctuations are calculated. In this paper it is assumed that only the elastic constants are affected by the variations in composition. As a result of these energy fluctuations, the dislocation line becomes slightly kinky. It is possible to calculate the mean energy barrier for motion of a double kink and also the average dimension of the double kink. The shear stress at 0°K is then determined. The results are compared to experimental data available for Au–Ag alloys and to other hardening theories.