Bonding interface zone of Mg-Gd-Y/Mg-Zn-Gd laminated composite fabricated by equal channel angular extrusion

In order to improve the mechanical properties and corrosion resistance of Mg alloys, the equal channel angular extrusion (ECAE) was employed to fabricate the Mg-5Gd-5Y/Mg-2Zn-1Gd (GW55/ZG21) laminated composites. After fabrication and annealing treatment, the microstructural evolution, phase constitution, microhardness, and bonding strength were investigated on the bonding interface zone of GW55/ZG21 laminated composites. The bonding interface zone of GW55/ZG21 laminated composites comprises a lot of Mg3(Y, Gd)2Zn3 particles along the bonding interface, some rod Mg24(Y, Gd)5 phases on GW55 side, and a precipitation free zone (PFZ) on ZG21 side. After annealing treatment, Mg3(Y, Gd)2Zn3 particles along the bonding interface increase, rod Mg24(Y, Gd)5 phases on GW55 side decrease, and PFZ is broadened. Meanwhile, the hardness on the bonding interface zone decreases and the bonding strength increases from 126 MPa to 162 MPa.