Nonmonotonic rate dependence of the dynamic yield strength of alloys under high strain rate deformation

The glide of edge dislocations in an aged binary alloy under high strain rate deformation is theoretically studied. An analytical expression for the rate de-pendence of the dynamic yield stress is obtained. The conditions are obtained under which the graph of the rate dependence can have two maxima and two minima. The existence of two maxima is associated with the presence of two types of defects that differ significantly in their sizes (atoms of the second component and the Guinier–Preston zone). The minima occur during the transition from the dominance of dynamic drag by one type of defects to the dominance of defects of another type. The maxima appear when the character of drag by dominant defects changes.