Fracture mechanism and toughness of a rolled magnesium alloy under dynamic loading

Static and dynamic fracture experiments are performed using fatigue pre-cracked three-point bend specimens of a rolled AZ31 Mg alloy on servo-hydraulic universal testing machine Hopkinson bar setup, respectively. The results interpreted in-situ optical imaging along with digital image correlation analysis. Microstructural analysis reveals that the mechanism changes from twin-induced quasi-brittle cracking for static loading to micro-void growth coalescence under accompanied by decrease in tensile twinning near tip rate. By contrast, density twins far-edge ligament associated texture change enhance strongly toughness increases dramatically at high rates which is attributed enhanced work separation dissipation background plastic zone.