Abstract
Micromechanisms of fracture of AZ61-F composites in the zone of quasi-superplastic deformation were analysed and quantified in this work. Deformation of AZ61-F magnesium alloys with 1 wt.% of Al₂O₃ phase was tested at a temperature of 473 K and different strain rates. It was shown that at the temperature of 473 K and the highest strain rate applied from 1 × 10^–2 to 1 × 10^–4 s^–1, a significant growth of ductility was observed. The mean dimples diameter of the ductile fracture decreased with decreasing strain rate. The grain size of 0.7 μm was reached by severe plastic deformation using equal channel angular pressing (ECAP). Secondary Mg₁₇Al₁₂ and Al₂O₃ phases were identified. The maximum strain was obtained at the temperature of 473 K and strain rate of 1 × 10^–4 s^–1.

Key words
AZ61-F Mg-Al₂O₃, fracture analysis, quasi-superplastic behaviour, kinetics process

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