Interfacial characteristics, mechanical properties and fracture behaviour of Al/Mg bimetallic composites by compound casting with different morphologies of Al insert

The effect of surface morphologies of Al insert, including smooth surface (SS), straight knurling (SK) and hatching knurling (HK) on interfacial microstructure, mechanical properties and fracture behaviour of Al/Mg bimetallic composites by a novel compound casting was studied in this work. The thicknesses of the interface layers of the SK-s and HK-s bimetallic composites, respectively, increased by 11.5% and 4.8% than that of the SS's composite. The interfacial phase compositions were similar for all the bimetallic composites, mainly consisting of eutectic layer (EU) and intermetallic compound layer (IMC). Therein, the proportion of the EU layer in the entire interface layer for the SK's and HK's bimetallic composites was larger than that of the SS's sample. The EU layer had a lower hardness than the IMC layer. The shear strengths of the SK's and HK's bimetallic composites increased by 34.2% and 50.2%, respectively, compared to that of the SS's bimetallic composite.