| Hypoeutectic Al-Si alloys can find more and more applications in the industry of aerospace and rail transportation due to their excellent properties of good castability,strong corrosion resistance,low shrinkage rate,small thermal cracking resistance,fatigue resistance and processability and low price.The alloys are usually refined or modified in order to improve the overall performance of alloys.The β-Al5FeSi phase from Al-10Si-2Fe master alloy and the original Fe in the melts can form local ordered(AlFeSi)clusters,which can promote the eutectic silicon nucleation and the eutectic cells as well.It is wise to take advantage of the negative factores(Fe)to improve the properties of alloys.This study aims to investigate the fabrication of the master alloy,the optimum of the inoculation parameters and the industrical production by analysis of the microstructure and mechanical properties.The inoculation effect of Al-10Si-2Fe the master alloy relies on its cooling rate.The β-Al5FeSi particles get refined and distribute more uniformed in the master alloy with higher cooling rate.The master alloy performs best when fabricated in the copper mold with 2.5 mm thickness.Thus the facility was improvement according to the results.The third generation facility with single copperroller and steel strip enables continuous and rapid production and enhances the production efficiency.More importantly,the quality and stablizaiton of the master alloy improves,making it possible for the industical production.It is found that Al-10Si-2Fe master alloy can refine eutectic cells and porosity and improve the mechanical properties of Al-9Si-0.45Mg alloys inoculated by Al-10Si-2Fe master alloy with different holding time and temperature.Al-10Si-2Fe master alloy can refine the eutectic cell and make up for the defect caused by Sr modification.Additionally,it can refine the size and distribution of porosity.The optimum holding temperature is in the low temperature range between 720℃ to 740℃.The master alloy remains its inoculation effect when holding for 30 min～120 min at 720℃,implying that it is a kind of long-acting inoculant.Al-10Si-2Fe master alloy is found to refine the morphology of iron-rich phase,the eutectic cell and silicon in A356 alloys by analysis the microsturcure,mechanical properties and fracture of A356 alloys inoculated with Al-10Si-2Fe master alloy.Especially,the elongation is incrased by 110%and 42.9%in the as-cast samples and samples with T6 treatment.The tensile strength is increased to a great extent.The experiments also provide technology guidance for industrial applications. |
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