Cyclic deformation of the alloy Cu-35%Ni-3.5%Cr in the homogenized condition

Abstract The cyclic deformation behaviour of the planar slip mode alloy Cu-35%Ni-3.5%Cr in the homogenized condition has been investigated at constant stress amplitudes. During cycling at stress amplitudes higher than the cyclic yield strength, an initial cyclic hardening followed by a cyclic softening was observed. TEM studies revealed that cyclic hardening is due to an increase of dislocation density and cyclic softening is mainly introduced by energetically favourable rearrangements of dislocations. The smallest plastic strain amplitude during cycling corresponds to a saturation dislocation density, which increases with increasing stress amplitude. The lifetime of this alloy can be correlated not only with the stress amplitude, but also with the smallest plastic or total strain amplitude.