Fabrication of Al/Mg Bimetallic Thin-Walled Ultrafine-Grained Tube by Severe Plastic Deformation

Abstract

Multilayer composites have recently attracted considerable attention due to their ability to take advantage of the benefits of various metallic materials simultaneously. The present study is the first to use parallel tubular channel angular pressing (PTCAP) as a severe plastic deformation method to fabricate a bimetal Al/Mg tube. This process was applied on commercially pure aluminum along with an AM60 magnesium alloy at the temperature range of 250-400 °C. According to the microstructural and mechanical tests, there is a strong bond between layers besides the grain refinement after the process. Additionally, microhardness examinations showed that there is an excellent homogeneity in addition to the dramatic increase in the hardness of bimetallic PTCAP processed Al/Mg tube. Scanning electron microscope and energy-dispersive x-ray spectroscopy analyses in the interface between the layers and also the results of the shear strength test showed that by increasing the temperature, the diffusion rate at the interface increases. For instance, the significant bonding strength of 30 MPa was achieved after the PTCAP specimen at 400 °C. Therefore, these investigations substantiate that the PTCAP process can be used as an appropriate cladding technique for obtaining simultaneous severe plastic deformation microstructures and sufficient bonding strength in the production of bimetallic tubes.