Study on static precipitation、recrystallization and texture evolution of Mg-8.07Al-0.53Zn-1.36Nd rolled magnesium alloy during heat treatment

Abstract:

_{: Themicrostructure and texture of Mg-8.07Al-0.53Zn-1.36Nd magnesium alloy were characterized by SEM、EBSD and EDS.The results show that the heat-treated alloy is mainly composed of α-Mg matrix, β-Mg17Al12 precipitates and Nd-containing compounds. The bimodal grain structure ofβ-Mg17Al12 precipitates zones andfree zonein the alloy after heat treatment below 400℃. A large number of nanoscale granular β-Mg17Al12 precipitates mainly along the deformation zone and twin interface are precipitated first,andthen the static recrystallization of α-Mg matrix formed. With the increasing of annealing temperature, the amount of β-Mg17Al12 decreases, and the size and amount of rare earth phaseshaven’tbeen changed significantly. The static recrystallization occurs preferentially in the precipitates-free zones ofβ-Mg17Al12 precipitates in bimodal grain structure, which indicates that the precipitation particles can delay the static recrystallization. Theβ-Mg17Al12 precipitates in the alloy after heat treatment at 400℃ are dissolved and the amount is reduced significantly.The magnesium matrix recrystallized completely and the recrystallized grains grew up significantly. EBSD results show that the texture of the experimental alloy after heat treatment is mainly weakbasal texture, accompanied by part of the non-basal texture. In the alloy after heat treatment below 400℃, a large number of β-Mg17Al12 precipitates play an important role in weakening basal texture. With the increasing of heat treatment temperature, the dislocation density in the alloy decreases, and the main texture components change from {0001}< 10-10 > deformation texture to {0001}< 11-20 > recrystallization texture.}

Key words:Mg-Al-Zn-Nd alloy; heat treatment; static precipitation; recrystallization; texture