Hot Tensile Behavior of the Laminated Al/Mg Composites Produced by Roll Bonding
摘要
In the current study, the Al/Mg/Al bimetallic composite was prepared by roll bonding at room temperature. Subsequently, hot tensile deformation of the laminated composites was evaluated under 0.001–0.1 s−1 at 150–350 °C. The results showed that the bimetallic layered composite has high strength along with high ductility at high working temperatures. By calculating the constitutive equations, it was determined that the calculated activation energy of the composite is less than the self-diffusion energy in its constituent elements (Al and Mg). Also, the stress exponent was calculated to be 6, which indicated the dislocation slip mechanism. The results showed that the recrystallization due to cold working during rolling led to grain boundaries strengthening, which creates obstacles for the movement of dislocations and increases the resistance to hot plastic deformation. By drawing the hot deformation map, it was determined that there is no instability zone in the temperature range of 150–350 °C and strain rates of 0.001–0.1 s−1, and the safe zone is in the range of 250–350 °C for all strain rates. Examination of the fracture surface of the composite samples showed that cavitation at the interface of the layers was the dominant mechanism of failure.