Superplastic behaviour of Al-Mg-Zn-Zr-Sc-based alloys at high strain rates

Superplastic deformation behaviour of two aluminium-based AA7XXX type alloys with Sc and Zr additives distinguished by the presence and absence of coarse eutectic Al9FeNi particles are compared. An alloy with Al9FeNi particles exhibits high strain rate superplasticity at constant strain rate range of 5×10−3-8×10−2 s−1 with elongation of 915% due to extensive dynamic recrystallisation. Effective activation energy of superplastic deformation, surface relief of deformed samples, and grain structure evolution are analysed. Particle-depleted zones are found in the alloy with Al9FeNi particles at strains higher than 1.25.