A Novel Forming Process of Mg/Al Composite Square Tube Based on Numerical Simulations and Experiments

In this paper, a novel process for the preparation of Mg/Al composite square tubes is presented. The straight wall and corner of the composite square tubes were scanned and analyzed by scanning electron microscopy(SEM), energy dispersive spectrometer(EDS), and X-ray diffraction(XRD) at different stages. The results show that the metallurgical bonding of the bonding layer produces two kinds of intermetallic compounds(IMCs), the metallurgical bonding effect is influenced by the multi-factors, and the corners are prone to defects. The causes of defects at the corners of the composite square tube were studied and analyzed using DEFORM-3D software. The results of electron backscattered diffraction(EBSD) showed that the PEF process could significantly refine the microstructure of the magnesium alloy in the composite square tube, reduce textures intensities of magnesium alloy (0001) basal plane, and increase the Schmid factor(SF) values of magnesium alloy (0001)< 11–20 > slip system. {10−12} tensile twins appear during the upsetting stage, followed by continuous dynamic recrystallization(CDRX). In the sizing stage, the proportion of DRX was ∼24.6%. The PEF process can improve metallurgical bonds in Mg/Al composite square tubes by applying shear forces and has great potential in improving the comprehensive properties of Mg/Al composite square tubes.