Intermetallic compounds and antiphase domains in Al/Mg compound casting

Interfacial microstructure of Al/Mg light metals couples prepared by compound casting process was studied. The interface consists of three different layers. The layers adjacent to the Al and Mg base metals are mainly composed of Al3Mg2 intermetallic compound and (Al12Mg17+δ) eutectic structure, respectively, and the middle layer is mainly composed of Al12Mg17 intermetallic compound. A network of periodic antiphase domains (APDs) was detected within the Al12Mg17 intermetallic compound at the middle layer. The size of the APDs was not constant throughout the layer containing this intermetallic compound and was depended on the amount of deviation from the stoichiometric proportion (SP) of the Al12Mg17 intermetallic compound. It was found that by increasing the deviation from the SP the size of the APDs of the Al12Mg17 intermetallic compound decreases and the density of the antiphase boundaries (APBs) increases.