Characterization of aluminium matrix compositesreinforced by Al–Cu–Fe-Cr quasicrystalline particles

Abstract

The Al63Cu25Fe9Cr3 quasicrystalline was prepared by conventional casting method. The microstructures and phase composition of Al63Cu25Fe12 quasi-crystalline and Al65Cu20Fe10Cr5 phases were characterized by XRD and SEM. Aluminium based composites was fabricated by using the Al63Cu25Fe9Cr3 quasicrystalline particles as the reinforcing phase and ZL101 as matrix with mechanical stirring. The effects of quasicrystals content, on the microstructure and mechanical properties of the obtained composite, were investigated. The results show that the as-cast quasicrystalline material is composed of d-phase(Al65Cu20Fe10Cr5), I-phase(Al63Cu25Fe12), λ-Al3Fe, β-AlFe3 and a small amount of η-AlCu, θ-Al2Cu phases. After heat treatment, the quasicrystalline intermediate alloy composition tends to quasicrystal phase. In the composite material, the diffusion between the quasicrystalline and the matrix alloy caused the decomposition of the structure of quasicrystalline phase. With the increase of quasicrystalline content, the tensile strength of the composites increases. However, addition of the Cr element changes the acicular β-Fe(Al80-85Fe6-9Si10-15) phase into a man-like or bone-like α-Fe(Al80-85Fe4-8Si6-8Cr3-5) phase which increases the elongation of the composite. The best comprehensive mechanical properties corresponded to the 7 wt% quasicrystalline particles. Strengthening mechanism of quasicrystal reinforced aluminum matrix composites, a model that model considers the dislocation strengthening mechanism and the effect of load transfers mechanism on the tensile strength of composites. This theory calculates the tensile strength of quasicrystalline reinforced aluminum matrix composites and verifies the effectiveness of the model through experiments.