Effect of γ precipitates on the cavitation behavior of wrought AZ31 magnesium alloy

In the present work, the influence of γ eutectic phase on the cavitation behavior of wrought AZ31 magnesium alloy has been studied through applying a set of low strain rate hot tensile tests. The tensile tests were executed in two temperature range of 300-425 °C and 450-500 °C; i.e. somewhat below and higher eutectic melting temperature of γ precipitates (∼437 °C). The hot compression characteristics of the experimental alloy were also considered to assist explaining the related deformation mechanisms. The results indicated that a large amount of cavities originates from the γ second phases, specially located on grain boundaries. A sharp transition was realized from higher ( > 3%) to lower cavity area fraction ( < 0.02%) between 450 °C and 500 °C. The latter was attributed to the effect of γ liquid phase on stress relaxation through accommodating the grain boundary sliding phenomena. In addition, the current work explores the room temperature mechanical properties of tensile deformed specimens using shear punch testing method.