Flow stress and rheological behaviour of model Al-Mg alloys during hot plane strain compression

The influence of Mg content, temperature and strain rate on the plastic flow behaviour of model Al-Mg alloys has been investigated by high temperature channel-die experiments. Four model alloys (AA1070 + 0, 1, 3 and 5 wt.% Mg) have been deformed in plane strain compression to strains of unity at temperatures between 20 and 500 degrees C and strain rates of 10(-3) to 10 s(-1). The work hardening and strain rate sensitivity relations have been analysed in terms of different models. A Kocks-Mecking analysis modified to include three strain hardening stages (II to IV) gives a satisfactory representation of the rheological behaviour. The influences of temperature and strain rate on the work hardening coefficients of this model are described and discussed.