Undercooling and supersaturation of alloying elements in rapidly solidified Al-8.5% Fe-1.2% V-1.7% Si alloy

Dispersion-strengthened Al-8.5% Fe-1.2% V-1.7% Si alloy was produced by inert gas atomization and atomized melt deposition processes. Differential scanning calorimetry was used to estimate the extent of undercooling in the alloy powders as a function of powder size and in the atomized melt-deposited alloy as a function of process parameters. The estimated undercooling was found to be a strong function of powder size and processing conditions and varied from 380–200 °C. Alloy powders of diameter greater than 180 jam did not experience any undercooling during solidification. X-ray diffraction analysis was performed to study the dependence of supersaturation of alloying elements and metastable phase formation on the extent of undercooling. When the undercooled alloy was heated to about 400 dgC, formation of Al₁₂(Fe, V)₃Si phase with b c c crystal structure from the supersaturated matrix was observed.