余温轧制对Al-Mg-Si合金组织演变的影响

Effect of residual temperature rolling on microstructure evolution of Al-Mg-Si alloy

采用金相组织观察、扫描电镜和X射线衍射技术研究了余温轧制压下量对Mg/Si比值为1.5时的Al-Mg-Si合金组织演变的影响规律与作用机理。结果表明,在370℃余温轧制时,随着余温轧制压下量的不断增加,晶粒尺寸越来越小,细小等轴晶数量增多。余温轧制后,板材大部分晶粒仍然保持着铸轧态的柱状枝晶形貌。但是随着压下量的增加,晶粒尺寸减小,板材边部细小等轴晶数量增多,心部气孔和疏松得到部分愈合,合金板材成形性能显著提高。由此推断,余温轧制可以促进合金形成更多更细小的再结晶晶粒,使合金组织均匀,从而显著提高组织性能。

The effect of residual temperature rolling reduction on microstructure evolution of Al-Mg-Si alloy with Mg/Si ratio of 1.5 was studied by means of metallography observation,scanning electron microscope and X-ray diffraction.The results show that the grain size becomes smaller and the number of fine equiaxed crystals increases with the increase of the rolling reduction at 370℃.After residual temperature rolling,most grains of the sheet still maintain the columnar dendrite morphology.However,with the increase of the reduction amount,the grain size decreases,the number of fine equiaxed crystals on the edge of the sheet increases,the gas hole and porosity in the heart are partially healed,and the formability of the alloy sheet is significantly improved.It is concluded that the residual temperature rolling can promote the formation of more and finer recrystallization grains,homogenize the alloy structure,and signifi-cantly improve the microstructure properties.