少量Ag对低Cu／Mg比的Al-Mg-Cu-Li合金组织与性能的影响

Effect of Minor Ag Addition on Microstructures and Properties of Al-Mg-Cu-Li Alloy with Low Cu/Mg Ratio

通过显微硬度测试、拉伸试验、能谱分析、SEM及TEM观察,研究了少量Ag对低Cu／Mg比的Al-Mg-Cu-Li合金微观组织与性能的影响。实验结果表明:Ag的添加提高了该合金的硬度和强度,同时改善了其塑性,并延缓了过时效的发生。微观组织观察表明:Ag的添加促进Z相的均匀弥散析出,同时抑制了S'相在缺陷处非均匀析出;并且Ag的添加还促使了时效初期合金中δ'相的细化和弥散分布,延缓了δ'相的长大。同时分析了析出相种类对合金塑性的影响。

The effects of Ag addition on the Al-Mg-Cu-Li alloy with low Cu/Mg ratio were studied by microhardness testing, tensile testing, SEM and TEM. The mechanical testing results indicated that the Ag addition increased the microhardness, ductility and strength of the alloy, and retarded its overaging process. The microstructural analyses showed that Ag stimulated the uniform and dispersed the precipitation of Z phases and inhibited the heterogeneous nucleation of S＇ on the defects. Also Ag facilitated the dispersed distribution of δ＇ phase at the early ageing stage and retarded its growth in the further ageing duration. The ductility of alloys was discussed on the base of the nature of precipitates.