Effect of temperature on the stages and localization of plastic deformation in a copper-nickel alloy

It is known that plastic flow occurs with macroscopic strain localization. The macrolocalization pattern depends on the stage of the stress-strain curve. Here we experimentally demonstrate three hardening stages for copper-nickel alloy constantan (CuNi44Mn1): yield plateau, linear stage, and parabolic (Taylor’s) stage of strain hardening. The prefracture stage is absent. Upon completion of the parabolic stage, the sample almost immediately reaches the ultimate strength, the total stress drops and necking begins. An increase in the deformation temperature from room temperature to 2000C changes the duration of the observed strain hardening stages. The yield plateau length increases by a factor of two with a general 10% decrease in ductility. The duration of other stages does not almost change or decreases insignificantly within 1% strain. The parameters of plastic strain localization at the given deformation stages at room and elevated temperatures are measured by digital image correlation. The kinetic parameters of the localized deformation fronts are calculated.