Microstructures and mechanical properties of conventionally solidified Al63Cu25Fe12 alloy

Abstract

In this study, the microstructures and mechanical properties of conventionally solidified Al63Cu25Fe12 alloy after different heat-treatments were investigated. The microstructures of the as-cast and subsequently heat-treated samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The XRD results showed the presence of quasicrystalline icosahedral phase (i-phase) together with crystalline phases corresponding to beta-AlFe(Cu) solid solution phase (beta-phase) and tau-AlCu(Fe) solid solution phase (tau-phase). The SEM investigations clearly showed the formation of i-phase with pentagonal dodecahedra structure. However, the i-phase together with beta-phase was also observed in the heat-treated samples and the peak intensity of the beta-phase decreased with increasing heat-treatment temperature. From the DTA curves, the melting point of i-phase was determined as 890 degrees C for this alloy composition. Mechanical properties of the as-cast and subsequently heat-treated samples were measured by a Vickers indenter. Results showed that the microhardness (HV) and the elastic modulus (E) of the as-cast sample were around 598 kg fmm(-2) (5.86 GPa) and 104 GPa, respectively. In addition, the characteristic of material plasticity (delta(H)) value was calculated to be 0.54. (C) 2010 Elsevier B.V. All rights reserved.