Co-extrusion of dissimilar AA6063/AA7075 by porthole die at various temperatures

Abstract

The dissimilar AA6063/AA7075 plate was fabricated by porthole die co-extrusion method, and the effects of extrusion temperature on microstructure and mechanical properties were investigated. The results showed that the sound AA6063/AA7075 welding interface without crack or impurity was obtained. Few secondary particles existed in extruded AA6063 side, while large amount of fine particles were found in AA7075 side, and the number of particles was decreased with increasing temperature. The coarse initial grains with the formation of substructures were observed in AA6063. However, the microstructure of AA7075 mainly consisted of fine equiaxed grains with several microns due to the occurrence of near complete dynamic recrystallization. The average grains size of the AA6063/AA7075 extruded plate was increased with increasing temperature. The plate extruded at 510 °C has strong texture component with 10° shift of Φ from Cube and some weak recrystallization Cube texture. The elongation was not affected by temperature, while the hardness and ultimate tensile strength were obviously enhanced with increasing temperature.