Al3(Sc, Zr) precipitation in deformed Al-Mg-Mn-Sc-Zr alloy: Effect of annealing temperature and dislocation density

Abstract The changes of Al3(Sc, Zr) morphology in deformed Al-Mg-Mn-Sc-Zr alloy were studied. Two experiment conditions were designed: different temperature and different dislocation density. Different dislocation density was obtained by different deformation method (traditional hot extrusion and equal channel angular pressing (ECAP)). It is calculated that the ECAP introduced a large amount of dislocations into the alloy and these dislocations accelerated the recrystallization making the interfaces move drastically. It is found that annealing the extruded sample at for 1 h does not cause the loss of coherency of the Al3(Sc, Zr) particles whether under 450 °C or 550 °C. However, annealing the ECAP sample at 450 °C causes a small amount of the particles loss of coherency. The main reason is that the grain boundary cut through the particle. Annealing the ECAP sample at 550 °C would cause most of the particles to lose coherency, and there are three main types of incoherency.