Optimization mechanism of matrix microstructure evolution on strength-plasticity of Mg/Al composite plate during hard-plate accumulative roll bonding

Mg/Al composite plate combines the light weight of Mg alloy and the plasticity and corrosion resistance of Al alloy, which significantly enhances its comprehensive performance. However, the long manufacturing cycle and high process requirements limit the rapid development of heterogeneous composite plate forming technology. Therefore, a new method of ARB (accumulative roll bonding) forming with hard plates is proposed in this paper. The results show that the tensile strength of Mg/Al composite plate can reach 235 MPa and the elongation is 14.7% at 3ARB. There are obvious dimples in the magnesium plate, which are ductile fracture characteristics, and the overall performance is the highest. Since the basal slip and non-basal slip of the Mg plate start at the same time, which promotes the formation of dynamic recrystallization. At this time, the recrystallization ratio of the Mg plate is 77.21%. With the progress of ARB, the high angle grain boundary increases and the grain refinement is obvious. The original grains have been basically broken and refined into equiaxed grains. The hardness fluctuation of Mg and Al matrix decreases gradually, and the internal structure of the composite plate tends to be stable. This provides a new idea for forming and manufacturing high-performance heterogeneous composite plates.