Deformation behaviour in α/β two-phase super-plastic brass

Abstract

α/β brass consists of hard α and soft β phase in its superplastic temperature range. Because of the difference between their mechanical properties, the superplastic behaviour of the alloy differs from that of other single-phase and quasi-single-phase alloys. The mechanical properties and microstructure of leaded α/β brass during superplastic deformation were studied and the mechanism is discussed. It is shown that the boundary diffusion controls the superplastic deformation process and boundary sliding is the main deformation mechanism; there is little deformation in the α-phase, and intragranular slip as the accommodating mechanism mainly occurs in β-phase in the superplastic range. It is also shown that the bulk diffusion dominates the deformation process, and intragranular slip is the main mechanism in the non-superplastic range.