Physical aspects of plastic instabilities

Serrated yielding is observed in Al-Mg and Al-Zn alloys if they are deformed at suitable strain rate at room temperature. To describe the physical origin of plastic instabilities, the critical strain at which the instabilities begin is investigated as a function of strain rate. This paper describes how a combination of tensile testing with various experimental techniques, such as acoustic emission and resistivity measurements, and with a theoretical model, could help to elucidate the fundamental mechanisms.