AbstractThe effect of zinc content on the processing map for hot deformation ofβbrass has been studied in the temperature range 550–800°C and strain rate range 0·001–100 s−1in brasses containing 44, 47, 51 wt-%Zn. The three types ofβbrass exhibit superplastic deformation at temperatures of 550–800°,≦750°C, and 700–800°C, respectively, and at strain rates of<1 s−1. In the 47%Znβbrass, superplasticity is curtailed at 800°Cowing to abnormal grain growth caused by anomalous diffusion. In all threeβbrasses, superplastic deformation is dependent on the diffusion coefficient. At temperatures less than 700°C and in the strain rate range 0·01−1 s−1, the 51%Znβbrass exhibits a domain of dynamic recrystallisation caused by the presence ofγphase particles in the matrix. At higher strain rates (10 and 100 s−1), the brasses become microstructurally unstable, which is manifested by oscillations in the stress–strain curves and by adiabatic shear bands and strain markings in the micrographs.MST/1421