Air gap formation during solidification in cylindrical castings of pure aluminium and eutectic Al-Si

Abstract

Casting of aluminium and eutectic Al-Si in a cylindrical mould has been performed. The air gap formed between the inner mould wall and the solidified shell was measured throughout the solidification process. Simultaneously the temperature distribution in the metal and the mould was measured. Calculations of the shrinkage of the metal were performed. The shrinkage due to thermal contraction was found to be too small to fit the measurements. A new model for the solidification process and the air gap formation was used, where the effect of the formation and condensation of lattice defects was considered. The condensation of lattice defects was used to explain the shrinkage and the air gap found experimentally.

Keywords:

• Air gap formation
• solidification
• aluminium
• cylindrical castings