Microstructure and Tensile Strength of an Al-Si-Fe-V Alloy: Vanadium and Solidification Thermal Parameters as Recycling Strategies

Abstract

One of the greatest challenges facing the recycling of Al-based alloys is handling Fe incorporation. The formation of Fe-rich phases has negative impacts on the mechanical behavior and may limit the usage of recycled alloys. In this context, V addition is regarded as a potential solution since it can inhibit the formation of such phases. However, the microstructure evolution of V-modified Al-based alloys is not fully understood, especially when different solidification cooling regimes are considered. Thus, this work investigates the microstructure and tensile properties of an Al-7Si-1Fe [wt.%] alloy modified with a 0.5 wt.%V addition. Directionally solidified samples were produced and subjected to microstructure analysis and tensile tests. It was found that the addition of V reduces the fraction of β-AlFeSi particles because of the formation of new V-rich phases. This was determinant to improve the tensile properties for faster cooling conditions during solidification. For moderate and slow cooling regimes, however, the V-containing alloy had a less favorable mechanical behavior due to the formation of larger β-AlFeSi particles. Finally, quantitative relationships are proposed for the prediction of tensile properties from microstructural parameters using multiple linear regression analysis.