Mg含量对Al-xMg合金板材显微组织的影响

Effects of the Mg content on the microstructure of Al-xMg alloy sheets

借助金相显微镜和SEM观察,研究了Al-(2.86～9.41)Mg合金热轧板及其完全退火后板材的显微组织。结果表明:Al-(2.86～9.41)Mg合金热轧板的晶粒均沿轧向呈纤维状分布,当w(Mg)>6.44%,热轧板中出现明显的滑移网;w(Mg)从6.44%增大至9.41%,热轧板中滑移带变粗、滑移带网变密集,滑移网波及的范围变广。热轧板经450℃退火处理后均完全再结晶,晶粒形状趋于等轴状。w(Mg)从2.86%增加至9.41%对再结晶晶粒尺寸无明显影响。热轧板经450℃退火处理后,板材基体中存在大量沿轧制方向呈流线分布的AlFeSi相和沿晶界分布的β相,镁含量增加,Al Fe Si尺寸、数量和分布变化不大,但β相的数量明显增多、尺寸明显增大。

The microstructure of hot-rolled and annealled Al-（ 2. 86-9. 41） Mg aluminum alloy sheets were investigated by optical microscopy and scanning electron microscopy. The results show that the grain shape of hot-rolled Al-（ 2. 86-9. 41） Mg aluminum alloy sheets is fibrous drstributed along the rolling direction and there appear many slip line nets in the hot rolled alloy sheet when w（ Mg） exceeds 6. 44%. The slip bands become coarser,the slip line nets become denser and the slip line nets become more widespread as w（ Mg） increases from 6. 44% to 9. 41%. The hot-rolled Al-（ 2. 86-9. 41） Mg aluminum alloy sheets are fully recrystallized and the grains are equiaxed shape,the recrystallized grain size is not changed obviously as w（ Mg） increases from 2. 86% to 9. 41%. There are many micron AlFe Si-containing phases stretching along the rolling direction and β phases distributing along the grain boundary in Al-（ 2. 86-9. 41） Mg aluminum alloy sheets after being annealed at 450℃. The number,size and distribution of Al Fe Si-containing phases are seldom changed,whereas the size and the number of β phase both increase with the increasing of Mg content in annealled Al-（ 2. 86-9. 41） Mg aluminum alloy sheets.