Constitutive Equations in Creep of the AE44 Magnesium Alloy
The creep behaviour of the AE44 magnesium alloy was described by means of a variation of the composite model, already successfully used to analyse the behaviour of die-cast Mg-Al alloys. Since the microstructure of these alloys is constituted by primary Mg globules surrounded by a divorced eutectic formed by supersaturated a-Mg and precipitates, these materials were compared to a composite with soft (globules) and hard (divorced eutectic) regions, both deforming with a similar strain rate during creep. The strengthening role of the precipitates formed in the hard region during cooling from injection temperature and during creep was expressed by introducing a threshold stress. The agreement between experimental data and model was very good.
Marcello Cabibbo and Stefano Spigarelli
S. Spigarelli "Constitutive Equations in Creep of the AE44 Magnesium Alloy", Materials Science Forum, Vols. 604-605, pp. 357-365, 2009