Micromechanisms of Fracture of Magnesium Based Composite After Superplastic Deformation

The micromechanisms of fracture of AZ61 + 1 wt. % Al₂O₃ composite in the zone of superplastic deformation was analysed and quantified in this work. The specimens were tested at temperature of 200°C at different strain rates. Changing the strain rate, from 1x10^-2 s^-1 to 1x10^-4 s^-1, a significant growth of ductility was observed. At maximum value of superplasticity the fracture was transcrystalline ductile with dimples of two size categories. Based on the statistical analysis of fracture micromechanisms at the elevated temperature and strain rates of 10^-0- 1x10^-4 s^-1 hyperbolic dependency was depicted according to Gurland - Plateau theory.