Some Yield Phenomena in Polycrystalline Silver-Base Alloys

The sharpness of the initial yield observed with silver-base alloys depends, in the majority of instances, on both the type of solute and the temperature of deformation in the range from 100 to − 196° C. In two particularly interesting examples (Ag-6%As and Ag-6%Sb) a sharp yield, present at the higher temperatures, is completely absent at lower temperatures. The sharp yield at higher temperatures is attributed to Suzuki locking, while at lower temperatures the controlling factor is the impedance to dislocation motion due to the direct interaction between solute and dislocations. Unloading yield points at − 196° C were most obvious in silver and in Ag-6%Au and became less apparent in the other alloys. This was the result of increased impedance, which reduced the backward movement of dislocations when the specimens were unloaded.