Magnesium alloy particulates for Thixomolding applications manufactured by rapid solidification

Techniques based on a rapid solidification concept were explored for manufacturing particulates of magnesium alloys with the potential use as feedstock for Thixomolding®. Basic features of granulation methods are outlined along with dimensional, morphological, microstructural and chemical characterizations of particulates with a composition of Mg–9% Al–1% Zn. In spite of the known tendency of Mg and Zn to evaporate, the globule chemistry was within the alloy’s specification. The microstructure comprised of dendritic morphologies of α-Mg and Mg17Al12 phases where the content of the latter was reduced compared to the conventionally cast state. It is suggested that the microchemical and phase segregations which accompanied the morphology of fine equiaxed dendrites are the key factors which control the transformation of particulates during subsequent heating in a solid state and their melting behaviour.