HIGH-TEMPERATURE PLASTIC-DEFORMATION IN AL-ZN-MG-CU ALLOYS

The paper deals with the Al-Zn-Mg-Cu alloys which may exhibit the superplastic behaviour at temperatures about 773 K. The high-temperature plastic deformation of two Al-Zn-Mg-Cu alloys (V95 and ONZ 42 4222) is studied. A special attention is paid to the determination of the most important features of superplastic deformation - ductility and strain rate sensitivity parameter m. The differences in the deformation behaviour of individual materials are discussed on the base of structure studies using optical and transmission electron microscopy methods.