高合金化Al-Cu-Mg合金凝固组织的形成及表征

The Characterization of the Solidification Microstructures of the High Alloying Al-Cu-Mg Alloys

通过合金成分设计,采用常规铸造工艺在不同的凝固速度下制备原子比Cu∶Mg=1∶4的Al-2%Cu-8%Mg(原子分数,下同)、Al-3%Cu-12%Mg两种高合金化铝合金,利用XRD、OM、SEM、TEM等分析测试手段,观察了合金的组织特征。试验发现,除常规相α-Al和S相之外,两种合金中还存在多种非平衡相,Al-2%Cu-8%Mg合金晶界中存在纳米AlCuMg、Al12Mg17粒子,并且有类似相Al3Mg2生成,而Al-3%Cu-12%Mg合金的晶界相为亚微米Al12Mg17及AlCu、AlCu3相。

In this experiment, the two high alloying Al-2 at%Cu-8 at%Mg, Al-3 at%Cu-12 at%Mg alloys were cast in cuneal mould at different cooling rates after the delicate alloy composition design. Analytical and testing instruments such as XRD, OM, SEM, TEM were used to observe the microstructure and ascertain the phases of these alloys. It was found that there were several other phases except for the equilibrium phases α（Al）＋S. Among them, nanoscale crystal AICuMg, Al12Mg17 phases and crystalline approximant Al3Mg2 formed in AI-2 at%Cu-8 at%Mg,.however, the phases in Al-3 at%Cu-12 at%Mg grain boundary were submicron crystal Al12Mg17 and Al-Cu phases.