Influence of secondary warm rolling on the interface microstructure and mechanical properties of a roll-bonded three-ply Al/Mg/Al sheet

We investigated the influence of annealing and secondary warm rolling on the microstructural evolution and mechanical properties of a roll-bonded three-ply Al/Mg/Al sheet. After annealing at 300 °C, the formation of an intermetallic compound (IMC) layer consisting of Mg17Al12 and Mg2Al3 was identified at the interface. Although the thickness of the IMC layer increased with increasing annealing or preheating time, secondary warm rolling after preheating at 300 °C for 10 min significantly reduced the thickness of the IMC layer below 1.5 μm. Also an equiaxed and homogeneous grain morphology of the constituent magnesium alloy was successfully introduced. This resulted in strongly enhanced elongation up to magnesium fracture by 14.5%.