Mechanical Property and Fracture Behavior of Al/Mg Composite Produced by Accumulative Roll Bonding Technique

The Al/Mg laminated composite was fabricated by an accumulative roll bonding (ARB) technique using Al-1100 and Mg-AZ31 at 573？K. Tensile properties along rolling direction under different ARB cycles were evaluated at the ambient temperature. The tensile strength of the Al/Mg composite increased gradually till three ARB cycle and then decreased after the fourth ARB cycles. Scanning electron microscopy (SEM) was used to investigate the microstructure evolution and the failure mechanism. The Al/Mg interface with interface angles between 30° and 35° has minimum tensile strength. A higher or lower interface angle improves the tensile strength, and the interface angle can be reduced by increasing the number of cycles in the ARB process. Thus, the crack at the coarse intermetallic compounds and rupture of the Al layer after fourth cycle caused the premature failure of the specimens during the tensile test. 1. Introduction In recent times, the deformation and stability of metallic multilayers and the elastic and plastic behavior of multilayers under stress are increasingly being studied by researchers. Despite a broad range of investigations that include, for example, the study of the dislocation behavior in nanoscale multilayers [1, 2], a common feature of most such studies is that the true strain involved in the deformation process is less than approximately 1. Due to the limited strain involved, substantial changes in the layer arrangement and layer thickness are rarely encountered. Processing of fine-grained microstructures, even amorphous phases, by severe plastic deformation (SPD) has received considerable interest as a technique for strengthening metallic materials without a substantial degradation of ductility. Fine-grained microstructures of many kinds of metallic materials have been obtained by SPD techniques. A novel intense straining process involved in SPD for bulk materials using rolling deformation, termed accumulative roll bonding (ARB), was developed recently [3–6]. In this process, the achieved strain is theoretically unlimited. The ARB process has been successfully applied to aluminum alloy systems [7–10], steel systems [11, 12], copper systems [13], and layer-composite systems [14–16]. Most materials processed by ARB in several cycles have structures with submicron grains and show very high strength at ambient temperature [7–11]. Al/Mg layer compounds were successfully produced via an ARB process [14]. Al/Mg layer compounds exhibited excellent mechanical properties and showed refined grains. Diffusion occurred at the interface of Al and Mg