AbstractThe deformation behaviour of Cu–P alloys has been investigated by torsion and tensile testing over a range of strain rates and temperatures. The torsion flow curves are interpreted in terms of dynamic softening processes, and the curves obtained during interrupted testing are used to examine static-restoration behaviour. Constitutive equations relating flow strength to strain rate and temperature are deduced, with allowance made for the effect of deformation heating, and implications of the equation constants are discussed. It is shown from tensile results that a state of superplasticity can be achieved in alloys containing 3·8 and 6·8 wt-%P. Superplasticity can occur only if the smallαgrain size is stable and if the temperature and strain rate fall within certain limits. The activation energy associated with superplastic flow has been determined.MST/52