Structure of Al82Cu7Fe11 Alloy After High-Speed Quenching

Using structural analysis methods (metallographic, X-ray diffraction, differential scanning microscopy), a comprehensive study of the structure of Al82Cu7Fe11 alloy, obtained in the form of ribbons by the melt spinning method, was carried out. It is shown that a multiphase amorphous-nanocrystalline structure of high dispersity is formed in the alloy, which includes a solid solution based on aluminum, intermetallic compounds Fe4Al13 and CuAl2, and a small amount of a quasicrystalline phase of the composition Al–Fe–Cu with a tenth order symmetry axis (decagonal). The parameters of crystal lattices of phases and their volumetric content have been certified. It is shown that the main structural component of an alloy is iron aluminide, the content of which varies from 68 to 61 wt % across the ribbon cross section from the contact to the free surface. The temperatures of phase transformations in the alloy upon heating were determined. A comparative analysis of the structures on the basis of the phase composition and morphology of phases formed in rapidly quenched ribbons and an ingot of the same composition crystallized under equilibrium conditions was carried out. A difference in the alloy structure after different methods of crystallization has been established. The microhardness of the main structural components in the ingot was determined. Iron aluminide has a maximum hardness of 780 HV. It has been shown that the high hardness of 615 HV of the alloy after high-speed quenching is ensured by the formed multiphase amorphous-nanocrystalline state of the structure.