Effect of thickness of interfacial intermetallic compound layers on the interfacial bond strength and the uniaxial tensile behaviour of 5052 Al/AZ31B Mg/5052 Al clad sheets

Abstract

The thickness of intermetallic compound (IMC) layers at interface would significantly influence the interfacial bond strength, and the interfacial bond strength would further affect the tensile behavior of 5052 Al/AZ31B Mg/5052 Al tri-laminate structural clad sheets fabricated by hot rolling. In this manuscript, the relations among the thickness of IMC layers produced by post-roll annealing, the interfacial bond strength and the tensile behavior of clad sheets were investigated. No reactive diffusion phases were observed in the as-rolled clad sheets and in the rolled clad sheets annealed at 473 K for 1 h. When annealing at a temperature of 573 K for 0.5 h, 1 h, 2 h, 4 h, 8 h, new reaction diffuse phase layers with various thickness are formed at interface. Two types of reaction layers, viz., Al₃Mg₂ and Al₁₂Mg₁₇, adjacent to the 5052 Al side and AZ31B Mg side, respectively, are identified by EDS analysis. The effects of thickness of IMC layers on the normal bond strength and the shear bond strength were investigated. Uniaxial tensile tests of the clad sheets with and without IMC layers were investigated to reveal the relationships between the tensile behavior and the bond strength. Meanwhile, the fractured process of IMC layers and the delaminated process of tri-laminate composite sheets were also discussed during the uniaxial tensile testing.