Microstructure Characterization and Mechanical Property of Mg/Al Laminated Composite Prepared by the Novel Approach: Corrugated + Flat Rolling (CFR)

Abstract

In this paper, Mg/Al laminated composites were successfully prepared at 400 °C by corrugated + flat rolling (CFR) with reduction ratios of 35% and 25% and subsequent annealing treatments were conducted at 200–350 °C for 30 min. A two-dimensional model was established to analyze the strain distribution during the first corrugated rolling process. Simulation results indicated that severe plastic deformation was formed at trough positions, which included more numerous refined grains than in the peak positions. The interfacial microstructure and mechanical property of the flattened composites along the rolling direction (RD) and the transverse direction (TD) were investigated. The results revealed that longitudinal discontinuous and transverse continuous interfacial intermetallic compounds (IMCs) were observed of the flattened as-rolled sample. Spatial distribution was provided for the grain microstructure along the thickness and rolling direction for AZ31B magnesium alloys of the CFR as-rolled composite. Mechanical property results showed that the longitudinal ultimate tensile strength (UTS) and elongation (EL) of the as-rolled sample reached 255 MPa and 4.14%, respectively. The as-rolled UTS along TD reached 325 MPa, about 30% higher than that along the RD. After heat treatment, the anisotropy of mechanical properties remained. The microstructure evolution and mechanical properties were discussed in detail.

Interface Characteristics and Bonding Performance of the Corrugated Mg/Al Clad Plate

“…In addition to the ordinary compression deformation, the metals in the cross-shear zone are also acted on by the additional shear deformation [ 23 ]. The existence of the cross-shear zones will accelerate the fracture of the hard brittle layer and the exposure of the fresh metal, improve the interfacial bonding strength [ 24 ]. For the Mg/Al clad plate, there will be more slip systems of Mg plate in the cross-shear zone.…”

Asymmetric (Hot, Warm, Cold, Cryo) Rolling of Light Alloys: A Review

“…During the first corrugated rolling, compressive stress of various orientations is formed in the corrugated Mg/Al laminated composite [49]. This means that asymmetric deformation occurs, as shown in Figure 13 [49]. The upper corrugated roll results in an inhomogeneous local stress distribution at different positions.…”

“…The diameters of the corrugated and flat work rolls were both 150 mm [48]. During the first corrugated rolling, compressive stress of various orientations is formed in the corrugated Mg/Al laminated composite [49]. This means that asymmetric deformation occurs, as shown in Figure 13 [49].…”

“…In 2019, Wang [48][49][50] proposed the new asymmetric rolling process called "corrugated rolling and flat rolling" (Figure 12) to achieve strong interface bonding and substantial grain refinement in Mg/Al and Cu/Al layered composites. The surface of a corrugated work roll was designed as a sine curve with an amplitude of 0.5 mm and a period of 0.06 radians.…”

“…The Mg/Al laminated composites prepared by corrugated rolling and flat rolling exhibited outstanding tensile properties along both RD and TD, which can be attributed to the microstructure refinement induced by the severe shear strain. The tensile properties along TD were higher than that along RD in both the as-rolled and heat-treated state, and this significant anisotropy of the tensile property was mainly due to the microstructure spatial distribution and the interfacial intermetallic compound layer along the different directions [49]. Pesin et al [51] proposed asymmetric rolling based on the corrugated rolling and flat rolling process for the manufacturing of Al-steel layered composites with improved bonding strength between the stacked layers.…”