Effect of Extrusion Combination Types on Microstructure and Mechanical Properties of the AZ31/GW103K Bimetallic Composite Plates

The AZ31/GW103K bimetallic composite plates were prepared by co-extrusion of different combination types (sandwich extrusion type and double semicircle extrusion type), and effects of different extrusion combination types on the microstructure and mechanical properties of bimetallic composite plates were systematically investigated. The results show that both the AZ31/GW103K bimetallic composite plates prepared by different extrusion combination types have good metallurgical bonding, and changing the combination type does not affect the thickness of the interfacial transition layer of composite plates. Compared with the monolithic AZ31 and GW103K extruded plates, co-extrusion can promote the dynamic recrystallization (DRX) of AZ31 and GW103K components in composite plates, and double semicircular extrusion type has a better promotion effect on the DRX than sandwich extrusion type. In addition, the texture of AZ31 in both monolithic AZ31 and AZ31/GW103K/AZ31 (A/G/A) plates is a typical (0002) basal texture, while that in the AZ31/GW103K (A/G) composite plate shifts to the tangent direction (TD) of extruded plate. Compared with the monolithic AZ31 extruded plate, both the yield strength and tensile strength of A/G and A/G/A bimetallic composite plates are significantly improved. The strength of A/G/A composite plate is higher than that of A/G composite plate, but its elongation is worse. Meanwhile, co-extrusion reduces the dislocation density of AZ31 and GW103K components in composite plates, and different extrusion combination types also affect the dislocation density.