Al-Zn-Mg-Cu合金包铝薄板组织及弯曲性能

Microstructure and bending properties for Al-Zn-Mg-Cu alloy alclad sheet

采用显微硬度计、金相显微镜、扫描电子显微镜以及配套能谱仪,对厚度为6.32 mm的Al-Zn-Mg-Cu合金包铝薄板弯曲前后微观组织形貌差异及元素扩散情况进行表征与分析。结果表明:Al-Zn-Mg-Cu合金包铝薄板经过热轧复合处理后,过渡结合焊合界面区域平整光滑,无气孔空洞、氧化物夹杂等缺陷,过渡界面呈良好的冶金结合状态。包铝薄板包铝层厚向1/2位置到芯材的显微硬度呈逐渐增大趋势,且于200 HV附近稳定。包铝薄板基体组织中主合金元素在过渡界面内浓度呈梯度变化趋势。同时,包铝薄板经60°、90°、120°、150°及180°弯曲后,均未发现包铝层与芯材开裂的情况,板材弯曲性能良好,但随着弯曲角度的增大,表面变得更加粗糙。

The microstructure morphology differences and element diffusion conditions of Al-Zn-Mg-Cu alloy alclad sheet with the thickness of 6.32 mm before and after bending were characterized and analyzed by micro-hardness testers,metallographic microscopes,scanning electron microscopes and matching energy dispersive spectrometers.The results show that after hot rolling compound treatment,the transition bonding interface area of Al-Zn-Mg-Cu alloy alclad sheet is flat and smooth without defects such as pores,voids and oxide inclusions.The transition interface is in a good metallurgical bonding state.The microhardness of alclad sheet gradually increases from the 1/2 position of aluminum coating along the thickness direction to the core material,and stabilizes around 200 HV.The concentration of main alloy elements in the matrix structure of alclad sheet shows a gradient trend at the transition interface.At the same time,after bending at 60°,90°,120°,150°and 180°,no cracking is found between aluminum coating and core material.The bending performance of sheet is good,but the surface becomes rougher with the increasing of bending angle.