Aim of the BMWK TTP LB project “MAXImolding” (03LB3053C) is the development and construction of a casting machine utilising the deformation induced globulitic microstructure formation in semisolid magnesium alloys, specifically AZ91. Globulitic microstructure is favourable for both processing and material properties. The processing concept is based on patents held by project partner MAXImolding! Technology GmbH and uses no screw for shearing of the semisolid melt (compare classic Thixomolding), but a “thermal mass reactor” as the core component. Using high (~ 50 %) semisolid content, significant energy savings, compared to cold- or hot-chamber die casting could be achieved. As protective gas only ecologically friendly argon is needed. The underlying metallurgical effect was described early by e.g. Gebelin et al. (1999) and Czerwinski (2002). Design and construction of machine components is split between MAXImolding! Technology GmbH and project partner Dieter Enghausen Maschinenbau GmbH. Neue Materialien Fürth GmbH provides experience in magnesium processing and metallurgical analysis.

The congress contribution aims to give a short overview of the project in general and a more detailed description of the metallurgical effects and potential problems during semisolid thermal processing of magnesium alloy AZ91 without shearing. Only starting material with relatively high deformation results in the desired globulitic semisolid melt; relatively low deformation leads to the formation of dendritic solid phase. During continuous processing bridging of solid phase particles and melt decomposition into solid and liquid phases can hinder material flow.