Improvement of deep drawing formability of Mg-6Al-1Zn magnesium alloy sheets with high strength utilizing aging precipitation

The effects of aging precipitation on microstructure, deep drawing formability and tensile properties, were investigated for Mg-6Al-1Zn (AZ61) alloy sheets. The alloy aged at 175 degrees C for 96 h with high strength exhibited a significant improvement in deep drawability with an increased limiting drawing ratio (LDR) from 1.5 to 1.9, when slightly increasing deformation temperature from room temperature to 100 degrees C. This LDR (1.9) was even larger than that (1.75) of the unaged alloy drawn at 100 degrees C. The improved deep drawability can be attributed to the prevention of cracking at the edge of drawn cup, which is closely related to the restrictions of growth of tensile twins and basal slip due to Mg17Al12 precipitates, resulting in the delayed texture strengthening during deformation. The proposed idea of utilizing aging precipitation provides a new strategy for the development of Mg alloy sheets with superior deep drawing formability and high strength.

Automated summary

The effects of aging precipitation on microstructure, deep drawing formability, and tensile properties of Mg-6Al-1Zn alloy sheets were investigated. It was found that aging at high temperature significantly improved the deep drawability, resulting in an increased limiting drawing ratio. This improvement can be attributed to the prevention of cracking at the edge of the drawn cup by restricting the growth of tensile twins and basal slip through aging precipitation.