THE INFLUENCE OF THERMOMECHANICAL TREATME NT ON SUPERPLASTICITY IN ANAL-ZN-MG-CU ALLOY

The fine-grained structure resulting into superplastic properties may be prepared using a discontinuous static recrystallization in Al-Zn-Mg -Cu alloys. The grain size is generally influenced by some parameters of the thermomechanical treatment. The paper deals with the influence of the reduction by rolling and of the heating rate to the recrystalli zation temperature on the structure and mechanical properties. Superpl astic behaviour may be observed both in the fine- and coarse-grained m aterials. The influence of the grain size is studied in a broad range of strain rates.