On the mechanism of segregation band formation and its influence on the mechanical properties of pressure die cast magnesium alloys
(English)Manuscript (preprint) (Other academic)
Segregation bands which follow the contours of the outer surfaces of the casting are not uncommon in commercial magnesium pressure die castings. The presence of this type of defect has a strong detrimental effect on the mechanical properties. A few models have been proposed which tries to explain mechanisms behind the formation of this type of segregation bands. However, it is difficult to explain some phenomena which occur in real die cast components, using the models previously proposed. In this paper, a new model was suggested which is based on a coupled analysis of heat flow and volume changes during solidification. The formation of segregation bands was related to the pressure drop in the liquid, and the resulting flow of segregated liquid from the surrounding two-phase regions. Methods to prevent or decrease the formation of segregation bands have also been proposed and experimentally verified on real industrial castings. Finally, the influence of this type of defect on the mechanical properties of industrial castings has been studied and is presented in this paper.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-100379OAI: oai:DiVA.org:liu-100379DiVA: diva2:661714