In this study, a thermomechanical process consisting of general precipitation and severe plastic deformation through equal channel angular extrusion (ECAE) was applied to a Zn-22 wt.% Al alloy to produce a microduplex structure for high strain rate (HSR) superplasticity studies. Microstructures, hardness, and superplastic properties of the Zn-Al alloy were studied by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), recordable hydraulic press, and a tensile test with a hot stage. A work-softening phenomenon due to the occurrence of a grain boundary-sensitive dynamic recrystallization (DRX) was observed during the ECAE processing of the Zn-Al alloy at the extrusion temperatures investigated from -10 degrees C to 50 degrees C. An important discovery regarding the grain boundary-sensitive DRV was realized in this study such that through a progressive work-softening process the Zn-Al alloy will eventually exhibit HSR superplastic properties.