Increasing thermal conductivity in aluminium-copper compound castings: modelling and experiments

Compound cast heat sinks have various advantages over conventionally manufactured ones, but oxides present on the metals and formation of a brittle intermetallic layer (IMC) make casting difficult. In the present study, a novel approach was used that employs a silane-doped argon environment to overcome these issues. Oxidation could be fully suppressed and thermal heat conductivities around 67 W/(m center dot K) were obtained for the compound zone. The microstructural analysis revealed that the thickness of the IMC layer could be kept below the critical value of 3 mu m. Yet, the process window was found to be extremely tight. The modelling revealed that the critical time period for formation of the IMC layer is only on the order of a few 10 s.

Automated summary

Compound cast heat sinks have advantages over conventionally manufactured ones, but oxide formation and the presence of a brittle intermetallic layer (IMC) pose difficulties. A novel method using silane-doped argon environment was used to suppress oxidation and obtain a high thermal conductivity of 67 W/(m·K) in the compound zone. The IMC layer thickness was kept below the critical value of 3 μm. However, the process window was found to be very narrow, with a critical time period for IMC layer formation on the order of a few 10 s.