Towards Superplastic Forming of Az31 Magnesium Alloy with Controlled Microstructure

A recent study on post-superplastic forming properties has shown that heating time prior to testing has a major effect on the post-forming properties of superplastically-formed AZ31 Magnesium alloy sheets. To this point, there has been very little examination into the effects of pre-heating or annealing on superplastic forming. In this work, these effects are examined using AZ31 Mg alloy samples. Both tensile specimens and bulge sheets were Superplastically-stretched after undergoing different annealing routes. Multiple annealing temperatures and times were examined to produce specimens with grain sizes ranging from 8 to 15 μm, for comparison with traditional SPF results. The results show that annealing treatments can be suitable for the improvement of thinning and forming time of superplastically-formed Magnesium alloys through the control of the microstructure.