Recrystallisation behaviour of supersaturated Al–Mn alloys Part 1 – Al–1.3 wt-%Mn

The effects of concurrent precipitation on recrystallisation during the isothermal annealing of a supersaturated and deformed Al – Mn alloy have been investigated. At low annealing temperatures precipitation on the prior boundaries prevents recrystallisation whereas at high temperatures recrystallisation is complete before precipitation occurs. In the temperature range 375 – 500°C, recrystallisation is affected by precipitation and complex microstructures containing high fractions of low angle boundaries are formed. It is shown that strain induced boundary migration of very large boundary areas is an important recrystallisation mechanism in this temperature range. The interactions between precipitation and recrystallisation are analysed in terms of a simple model. The heating rate is shown to substantially affect the recrystallisation behaviour.