Optimized heat treatment for high pressure die cast aluminium components

Important results from the project

The purpose of the project wa sto increase thermal conductivity in cast aluminium to enable the use of aluminium in hot applications. Thermal diffusivity was increased by over 15% in the HPDC part and slightly less in the rheocast part. However, diffusivity is 20% in rheocastings compared to HPDC components even before heat treatment. Yield strength was estimated to increase by 75% since previous projects have shown this potential. Yield strength stayed however more or less the same, while ultimate tensile strength was increased by 13% and the elongation to fracture doubled.

Expected long term effects

When heat treating the components blisters arise at the surface at relatively low temperatures, which makes it difficult to reach the full potential of the material. To be able to heat treat high pressure die castings a substantial preparatory work is required regarding geometry and die design. Heat treatment, i.e. change of the microstructure, is a possible way to increase thermal conductivity. The influence of factors and effective approaches must be studied. The project contribute to increased knowledge in material science, die design and eventually increased sustainability.

Approach and implementation

Manufacturing and testing of Components have to a great extent been conducted by the g companies and the material investigations by the researchers in collaboration. The studies have been performed on real components, which makes it possible to compare properties. However, the possibilities of reaching the potential of the material and the heat treatment are limited since castings are influenced by the casting geometry. Future work needs to show the material potential regarding thermal conductivity and the possibility of designing properties with heat treatment and design.