Studying the Effect of Scandium on the Formation of a Quasicrystalline Phase in Al-Cu-Fe Ingots

Quasicrystalline ingots of the following compositions were obtained and studied: Al 63 Cu 25 Fe 12 ; Al 62 . 735 Cu 25 Fe 12 Sc 0 . 265 ; Al 62 . 56 Cu 25 Fe 12 Sc 0 . 44 . It is shown that 0.01% Sc is contained in the icosahedral quasicrystalline phase (Al 65.1 Cu 22.57 Fe 12.33 Sc 0.01 ). In addition to this scandium is contained in the intermetallic Al 51.45 Cu 37.29 Sc 8.23 (hexagonal W phase). It is established that alloying of the quasicrystalline Al-Cu-Fe alloy with scandium in the amount of 0.44 at. % significantly increases the content of the quasicrystalline icosahedral phase in ingots from 50 to 65 vol.% which leads to an increase in the microhardness of ingots. The microhardness of Al-Cu-Fe quasicrystalline ingots in the range of 20 - 400 °C is weakly dependent on temperature and amounts to 7-8 GPa. With increasing temperature, the microhardness value begins to decrease and at 720 °C reaches a value of 0.5 GPa. The study of the electrochemical characteristics of the corrosion process of quasicrystalline ingots showed that alloying of Al-Cu-Fe quasicrystalline alloy with Sc decreased the corrosion rate of non-annealed samples, and simultaneously lowered both the corrosion potential and the pitting potential.