Micro Deep Drawability of the Superplastic Zn-22Al Alloy at a High Strain Rate and Room Temperature

This study aimed to investigate the micro deep drawability of the Zn-22Al alloy at room temperature in which it shows superplastic properties. To this goal, first the two-step equal channel angular extrusion (ECAE) process was carried out to obtain an ultra-finegrained structure (UFG). Upon achieving the grain size of 200 nm, the formability of the alloy at room temperature and at a high strain rate was investigated both experimentally and numerically. Micro deep drawing experiments were performed at different deep drawing ratios (1.66, 1.84, 2.0, and 2.25) and for different sheet thicknesses (0.2, 0.4, and 0.6 mm). The finite element model of the micro deep drawing was also established to assess and compare the thickness variation in deep drawn parts. Results showed that the superplastic Zn-22Al alloy has a great potential in microforming applications. It was also noted that the limiting drawing ratio can be obtained as high as 2.25 in the room temperature condition.