不同状态条件下AZ80镁合金微观组织演化

Microstructure evolution of AZ80 magnesium alloy under different states

摘要:

利用电子背散射衍射（EBSD）技术观察研究了不同状态条件下AZ80镁合金微观组织，分析了不同状态条件下AZ80镁合金微观组织演化。结果表明：按照铸态、均质化热处理态和塑性变形态顺序，试样平均晶粒尺寸逐渐减小，平均晶粒形状纵横比呈“先增大后减小”变化趋势，网状β-Mg17Al12相逐渐消失，材料塑性和强度得到提高；晶界的协调作用主要受晶界迁移与几何必须位错密度两方面的影响，伴随晶界的迁移，小角度晶界逐渐增多并阻碍再结晶的进行，使再结晶区呈“先增大后减小”的变化趋势，而亚结构区则逐渐减小，亚结构区的消失为孪晶的形成提供了能量，促进了孪晶的形成；几何必须位错密度呈“先减小后增大”的变化趋势，几何必须位错密度的减小促进了孪晶的生长和晶粒间的旋转移动，而几何必须位错密度的增大则使孪晶的生长和晶粒间的旋转移动受到阻碍。塑性变形态镁合金出现了典型的基面织构。

Abstract:

The microstructure of AZ80 magnesium alloy under different conditions was observed and studied using electron backscatter diffraction (EBSD) technology, the microstructure evolution of AZ80 magnesium alloy under different conditions was analyzed. The results show that in accordance with the order of as-cast, homogenized and deformed states, the average grain size gradually decreases, the average grain shape aspect ratio showed a trend of increasing first and then decreasing, the network β-Mg17Al12 phase gradually disappeared, improved plasticity and strength of the material. The coordination of grain boundaries is mainly affected by grain boundary migration and geometrically necessary dislocations density, with the migration of grain boundaries, the low-angle grain boundaries gradually increase, which hinders the progress of recrystallization, and the recrystallization area has a tendency of increasing first and then decreasing, the substructure region gradually decreases, and the disappearance of the substructure region provided energy for the formation of twins and promoted the formation of twins. The geometrically necessary dislocations density has a trend of reducing first and then increasing, the decrease of geometrically necessary dislocations density promotes the growth of twins and the rotational movement between grains, the increase of geometrically necessary dislocations density hinders the growth of twins and the rotational movement between grains. The deformed magnesium alloy has a typical basal texture.