STUDY OF THE DOMAINS OF PORTEVIN-LE CHATE LIER PLASTIC INSTABILITIES IN THE ALUMINUM-MAGNESIUM ALLOY AG3

Plastic instabilities associated with the Portevin-Le Chatelier (PLC) effect, were studied in an aluminium-magnesium alloy AG3, in large ran ges of temperature as well as of strain and stress rates. Experimental results presented in a log sigma - 1/T or log epsilon - 1/T diagram, show that the region of PLC effect is closed at high loading rates. Th e critical strain at which the PLC phenomenon appears, increases when the loading rate increases at low temperature or at high loading rates . The ''inverse'' behaviour branches are observed at high temperature and at low loading rates.