Interfacial evolution and mechanical property of AZ31BMg/5052Al clad plate manufactured by corrugated + flat rolling technique

Abstract

In this paper, AZ31BMg/5052Al clad plates were successfully fabricated at the temperature of 400℃ through corrugated + flat rolling (CFR) technique and the post-rolling annealing treatment was also conducted at 200℃ for 30min. The reduction ratios were 35% and 25% for the first-corrugated pass and the second-flat pass, respectively. The interfacial microstructure and mechanical property of the Mg/Al composites were investigated. The results showed that the severe corrugated surface and slightly wave interface for the first-corrugated Mg/Al composite, and flat surface and obvious corrugated interface for the second-flat Mg/Al plate were obtained after the CFR approach. Interfacial microstructure researches indicated that well-bonded interface can be observed after the first-corrugated pass and the intermetallic compounds (IMCs) formed at the intermediate heat treatment process broke and now interface appeared. What’s more, this new interface still existed at the 200℃annealed Mg/Al clad plate. The average grain size of Mg alloy at the trough position was smaller than that at the peak position no matter what the as-rolled or the 200℃ annealed clad plates were due to the inhomogeneous strain induced by the corrugated roller. Tensile test displayed that the as-rolled flat composite exhibited the highest tensile strength as 237MPa and elongation as 4.65%. While the tensile strength and elongation had an increase of the 200℃annealed plate up to 252MPa and 13.5%. The high strength of the CFRed Mg/Al clad plates can be mainly attributed to the grain refinement of the substrate and the corrugated interface.