Rotational outward solidification casting: An innovative single step process to produce a functionally graded aluminum reinforced with quasicrystal approximant phases

A secondary AlSi7.5Cu3-(Fe,Mn) alloy with small additions of Mn and Fe was processed by an innovative rotational outward solidification casting process to produce a functionally graded aluminum (FGA). A cylinder was produced in a single step presenting two well-defined metallurgically bonded layers (A and B) with distinct chemical composition, structure and mechanical properties. Both layers were deeply characterized through different techniques. Layer A microstructure has more than 50%vol. of the primary alpha-Al-12(Fe,Mn,Cr)(3)Si quasicrystal approximant phase embedded in an Al-FCC matrix. On the other hand, layer B presents the typical hypoeutectic microstructure of the conventional AlSi7.5Cu3 alloy. Microhardness of the primary alpha-Al-12(Fe,Mn,Cr)(3)Si phase and macro-hardness profile of the FGA were measured. It was found that the hardness of layer A is approximately 1.6 times higher than layer B. This new FGA may be an alternative for producing parts that require gradient properties such as, for instance, automobile engine blocks. (C) 2020 The Authors. Published by Elsevier Ltd.