Published online by Cambridge University Press: 26 February 2011
The ordered Cu2NiZn alloy is virtually unique in showing a changing antiphase domain structure according to annealing temperature. At low annealing temperatures there are isotropic domains and at high annealing temperatures there are cube-oriented domains characteristic of highly anisotropic boundary energies. This property allows a comparison of dislocation behaviour for otherwise identical materials: the roles of cube crossslip and cube glide can then be distinguished from other mechanisms, for example elastic torque effects and dipole formation. Mechanical properties and dislocation structures are examined over a range of test temperatures. The material having cube-oriented domain boundaries shows a much higher work hardening rate over an intermediate temperature range. Strengthening at low temperatures is dominated by dipole and multipole formation, whilst deformation above ambient temperature leads to the appearance of non-octahedral glide, more frequently on planes near {110} than near {001}. For the material with cube-oriented domain boundaries there is some evidence to suggest point blockage by cross-slip onto cube planes, leading to the higher work hardening rate at the intermediate temperature. This study emphasizes the multiplicity of slip systems which may operate and discusses the relative importance of anisotropic antiphase boundary energies and anisotropic elasticity effects.