The influence of cooling rate on structure and corrosion behavior of Al-Ni-Fe-Y alloys with lower aluminum content

The aim of this work was to investigate the structure and corrosion behavior of Al₇₉Ni₅Fe₅Y₁₁, Al₇₉Ni₅Fe₁₁Y₅, Al₇₉Ni₁₁Fe₅Y₅ and Al₇₉Ni₇Fe₇Y₇ alloys prepared by different cooling rates from the liquid state: slow-cooled ingots, cast into water-cooled copper mold plates, and melt-spun ribbons at the casting temperatures of 1150, 1200 and 1400 ℃. In the case of Al₇₉Ni₁₁Fe₅Y₅ (1200 ℃) and Al₇₉Ni₅Fe₅Y₁₁ (1400 ℃) alloys in the form of melt-spun ribbons, the amorphous structure was confirmed by XRD, TEM and DSC. Increasing the cooling rate from the liquid state by casting into a water-cooled copper mold resulted in an ultrafine-grained structure. Electrochemical tests in 3.5 % NaCl aqueous solution at 25 °C indicated that corrosion resistance increases with a higher cooling rate from the liquid state, especially for amorphous alloys.