The Study On Extrusion Preparation Of AZ31/6082 Composite Plate

Mg/Al laminate composite has low density, high specific strength and modulus, excellent damping capacity,and thus, find great potential applications. In the present project, a new method, accumulative extrusion bonding(AEB), was proposed to fabricate Mg/Al laminate composite. Microstructure and texture of extruded plates were systematically studied using EBSD, optical microscopy, XRD and SEM. The microstructure and texture evolution and the influence of constraint of Al layer to Mg layer on rolling ability and microstructure were also addressed. Our results show that:① AZ31/6082 composite plate are successfully fabricated using extrusion bonding. The extruded plate can be used for the next cycle of extrusion, realizing an accumulative extrusion process. The Mg layer in the extruded plate contains much fine and recrystallized grains as well as a small amount of deformed grains. The Al layer has elongated fiber structure containing a small amount fine grains. A new cycle of extrusion induce more homogeneous structure, while hardly refines the grains. Annealing treatment generates more equaxied grains. An annealing at higher temperature results in coarsening of grains.② In AZ31/6082 composite plate, the thickness of transition layer between Mg layer and Al layer increase with increasing the number of layers in the extruded rod. No necking or wave shape exist the as-prepared plate. A new cycle of extrusion increases the thickness of transition layer from several micrometer to 20 micrometer. The transition layer contains more Mg2Al3 near the region close to Al layer, while more. Annealing induces thickening of transition layer. Annealing at 450°C, melting of interface appears.③ The Mg layer in the composite plate contains {0001}<10-10>, while the Al layer contains much Copper, S and Brass. The inner layer and the surface layer have different texture components. The texture in Mg layer is typical extrusion texture of extruded Mg plate. The surface Mg layer has a strong basal texture, while the inner Mg layer has two double peaks tilting towards the extrusion direction. The prismatic planes also show a preferred distribution.④ The constraint of Mg layer by the surface Al layer can increase the reduction of Mg layer to 40%. The small grains leads to the absence of twinning in the rolled plate with a reduction of 20%. The rolled plate has a typical basal texture. The maximum intensity of plate increase with rolling reduction. The intensity without constrain further reduce the maximum intensity of basal texture.