Microstructural Modifications Produced by Nano-Metal-Phosphate Additions to Aluminum-Silicon Alloy by new System Projects

Abstract

Al-13Si alloy microstructure affected by separate additions of Nano-Metal-Phosphate, prepared by die-casting, to synchronize refine eutectic Si and modify eutectic Al is studied. The nucleation and growth mechanisms of the Si phase are discussed via morphology and kinetics analysis. The effects point out that the measurement of eutectic Si is refined to 0.37-2.46 μm and the morphology of the large platelet eutectic Si particles had been modified into the fine fibrous shape. The technique synchronizing consequences of Nano-Metal-Phosphate is related to the AlP and Al2O3 formation. These consist of the following, the impact of Al2O3 at the interfaced between the Al segment and Si particles for obstacle the growth and enhance the refinement of the eutectic Si. The impact of AlP acts to locate of heterogeneous nucleation for eutectic Si, consisting of three aspects: interaction of dopant elements with molten Al-Si alloy to shape the nucleation site with reducing the interface energy between liquid and Si phase and increase the activation of diffusion energy throughout the liquid-solid interface. The results improve the mechanical properties of modified Al-13Si alloy and thus attributed to reducing silicone partials dimension and fibrous structure of eutectic silicon, presence of substantial AlP and Al2O3 in-situ precipitation in the eutectic location and the volume fraction increase of uniform distribution.