Engineering the heterogeneous nuclei in Al-Si alloys for solidification control

Abstract

Aluminium alloys are particularly advantageous for transportation industries to reduce the weight of the vehicles and thus pollution. The optimisation of the performances of Al alloys can be achieved by engineering and enhancing the heterogeneous nucleation of the melt. In this work, we demonstrate how the inoculation of commercial Al-Si alloys by Nb-based phases permits to improve and control the solidification process. We show that NbB2/Al3Nb are potent heterogeneous nucleation substrates for Al-Si alloys. The improved nucleation makes the material structure less dependent on the processing conditions such as solidification time and chemistry of the alloy (i.e. Si content). This permits to design and fabricate lighter structural components with improved and more isotropic performances.