Effects of cooling rates on the solidification process of Al-Si-Mg alloy

The effect of cooling rates on the solidification process of Al-2.06wt% Si-1.58wt% Mg was experimentally investigated. The solidification paths and the phase precipitation sequence were predicted coupled with the thermodynamic calculation. Due to the additional freedoms under the isothermal condition in multi-component alloys, the solute transportation and the solidification paths can be largely influenced by the cooling rates. It was proved through both experiments and calculation that different phase precipitation sequences were followed under different cooling rates. The solidification sequences are L → L₁+Fcc_Al → L₁+Fcc_Al+Si → L₁+Fcc_Al+Si+Mg₂Si under low cooling rate and L → L₁+Fcc_Al → L₁+Fcc_Al+Mg₂Si → L₁+Fcc_Al+Si+Mg₂Si under high cooling rate, respectively.