Mechanical Responses and Fracture Behaviors of Clad Mg/Al/STS Plates

Clad Mg/Al/STS plate comprised of Mg(AZ31), Al(Al 3004) and STS(STS 430) was fabricated by the roll bonding process and effect of heat treatment on the mechanical reliability was studied. Interfacial reaction compounds which have a detrimental effect were observed to be formed at the Mg/Al interface upon annealing at and above 300 °C. However, no visible interfacial reaction compounds were observed at Al/STS interfaces even after annealing up to 400 °C. The chemical compositions of reaction compounds at the Mg/Al bonding interface were analyzed using an Energy dispersive X-ray analysis (EDX) and the ratio of Al to Mg peak intensity was close to Mg₂Al₃ and Al₁₂Mg₁₇. The clad plates annealed at 200 °C showed a slightly increased ductility, suggesting the enhanced interfacial bonding. However, both the critical strain until the first drop of stress and the total fracture strain decreased with increasing annealing temperature and time, suggesting the detrimental effect of annealing at and above 300 °C.