The effect of microwave radiation on the formation of quasi-crystalline phases in the Al- Cu- Fe system prepared by induction furnace

Abstract

Aluminium- copper- iron quasi-crystals were prepared by melting raw materials and heat treatment process using microwave radiation at three temperatures of 600 °C, 700 °C, and 800 °C. Al- Fe alloy and Al- Cu alloy were prepared separately, then these two alloys were melted in an induction furnace. X-ray diffraction, scanning electron microscopy, and simultaneous thermal analysis were used to investigate the microstructural characteristics, fracture surface, and thermal behaviour. In these samples, the peaks related to the quasi-crystalline phase, θ, β- AlFe(Cu), λ- Al13Fe4, and ω-Al7Cu2Fe1 phase were detected. The intensity of the formed phases also changed with the temperature and duration of the heat treatment process. By performing the heat treatment process at 600 °C, the intensity of the peaks related to the quasi-crystalline phase has increased and the peaks related to the θ phase have completely disappeared. Also, by increasing the annealing temperature to 700 °C, the intensity of the peaks related to the quasi-crystalline phase increased compared to the sample annealed at 600 °C, but annealing at 800 °C reduced the intensity of quasi-crystalline phase peaks and λ- Al13Fe4 phase is completely dissolved, but some phases such as β- AlFe(Cu) and ω still remained, which implies these phases are stable even up to 1000 °C. The morphology of the quasi-crystalline was cauliflower with ridges on the fracture surface of the sample while uneven surfaces were in the form of quasi- cleavage. These results show that the quasi-crystalline phase can be developed in a much shorter time using microwave energy compared to common annealing methods.