A Continuous Extrusion‐Shear (ES) Composite Process for Significantly Improving the Metallurgical Bonding and Textures Regulations and Grain Refinements of Al/Mg Bimetallic Composite Rods

Abstract

To improve metallurgical bonding and texture regulations and grain refinements of Al/Mg bimetallic composite rods, Al/Mg bimetallic composite rods have been prepared by direct extrusion (DE) and extrusion‐shear (ES) processes. The bonding layers of the composite rods prepared by DE and ES processes with different preheating temperatures are investigated. Research results demonstrated that good metallurgical bonding layers with no voids and cracks are formed by the ES process with 390 °C, there are relatively poor bonding layers during the DE process and ES process with 330 and 360 °C. The microstructures and textures and dynamic recrystallization (DRX) evolution of Al/Mg bimetallic composite rods fabricated by the ES process are analyzed. Simultaneously, the microhardness and the shearing strength of bonding layers in the Al/Mg composite rods are investigated. The research results show that the grains are refined significantly due to DRX during the ES process. The texture intensities of basal planes <0001> and non‐basal textures <11‐20>,<10‐10> weakens as the preheating temperatures increased during the ES process. The DRX volume fraction is enhanced. The texture strength of the Al alloy weakens during the ES process, and the texture characteristics of the Al alloy changes obviously after the ES process. The ES process can improve metallurgical bonds in Al/Mg composite rods by applying shear forces and has great potential in improving the comprehensive properties of bimetallic materials.