The characterization of the solidification microstructures of the high alloying Al-Cu-Mg alloys

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 AlCuMg, Al12Mg17 phases and crystalline approximant Al3Mg2 formed in Al-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.