第二相尺寸分布对AA8111铝箔针孔率的影响

利用光学显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)、Image J和Nano Measurer等手段,研究了AA8111铝合金不同道次坯料组织中第二相尺寸分布规律。结果表明,7 mm铸轧板经5道次冷轧至成品坯料(0.24 mm)过程中,前期第二相破碎明显,尺寸变小,随着变形抗力的增加,后续轧制对第二相尺寸的影响越来越小;均匀化退火析出的棒状和圆盘状Si单质相对第二相尺寸分布影响较大,具有遗传性;成品坯料中第二相尺寸大于6 μm的占比8.9%,并存在部分尺寸为10 μm左右的较大第二相。与AA1235、AA8079合金的成品坯料进行对比分析,得出AA8111成品坯料中大于6 μm的第二相尺寸分布比例偏高是造成后续成品铝箔针孔率高的主要原因。

Effect of second phase size distribution on needle porosity of AA8111 aluminum foil

Size distributions of the secondary phase in different blanks of AA8111 aluminum alloy were studied by means of optical microscopy( OM),scanning electron microscopy( SEM),energy dispersive spectroscopy( EDS),Image J and Nano Measurer. The results show that during the 5 passes of cold-rolling from 7 mm cast-rolled sheet to the finished blanks of 0. 24 mm,the secondary phase breaks obviously and the size becomes smaller in the early stage,while with the increase of deformation resistance,the effect of subsequent rolling on the size of the secondary phase is getting smaller and smaller. The rod-shaped and disc-shaped Si elementary phases precipitated out during the homogenization annealing,have a great influence on the secondary phase size distributions and are heritable. The proportion of the secondary phase of greater than 6 μm in the finished blank is 8. 9%,and there are some larger secondary phases of about 10 μm. Compared with the finished blanks of AA1235 and AA8079 alloys,it is concluded that the high proportion of the secondary phase size distribution greater than 6 μm in the AA8111 finished blanks is the main reason for the high needle porosity of the finished aluminum foil.