Effect of Homogenizing annealing treatment on AZ91 magnesium alloy rolling deformation behavior

Abstract:

To improve the inhomogeneity and rolling forming ability of as-cast AZ91 magnesium, the effect of homogenizing annealing treatment on microstructure and mechanical properties of AZ91 magnesium alloy before and after rolling deformation was studied. The results showed that the distribution of second phase in the alloy tissue was improved effectively after homogenization annealing treatment. After multi-pass rolling at 400℃, the thin strip Mg₁₇Al₁₂ phase which originally distributed along the grain boundaries reduces significantly, with some of them fragmented, and some distributed near the grain boundaries or inside the grains as small particles. Compared with the strength of as-cast rolling structure, the strength of rolling structure after homogenization increases slightly; while the elongation increases by 50%.The tensile fracture morphology after rolling also shows that the ductility of alloy improves significantly. This lays a foundation for further study on the rolling forming of AZ91 magnesium alloy under different technological parameters.