Higher performance aluminum pressure die-cast alloys through refining

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Alloy and process development for aluminum pressure die-casting has until now been characterized by good castability and high strength coupled with good ductility. Refined pressure die-casting alloys have so far received little attention, since the aim of refinement is to refine the silicon precipitations, which in contrast to sand and permanent mold casting are already very fine in pressure die-casting due to the high cooling rates. However, new challenges, in particular due to electro-mobility, are now also bringing the thermal and electrical conductivity of the components into focus. The aim of this proposal is to systematically research the effect of refining conventional pressure die-cast alloys (AlSi9Cu3(Fe), AlSi10MgMn and AlSi12Cu1(Fe)) with strontium and finally to use it specifically to significantly (> 20%) improve the conductivity of aluminum die-cast components without affecting other properties. The aim of the refinement is to convert the normally plate-shaped, compact Si precipitations into interpenetrating structures with the matrix in order to considerably reduce their high electrical and thermal resistance. Subsequent heat treatments adapted to the refinement should further increase this effect and also help to increase the conductivity through the formation of precipitations and the associated reduction in the content of solid solution hardeners in the matrix. Furthermore, an understanding of how the conductivity develops within a die-cast component and in particular as a function of the cast wall thickness as a function of the alloy composition and the process parameters will be developed. Based on these findings, a targeted selection of suitable refinement contents, process strategies and heat treatment strategies to increase the conductivity of pressure die-cast components will ultimately be derived.