Directional solidification of aluminum-copper alloys

ARES, ALICIA;; RUBENS CARAM; SCHVEZOV, CARLOS

Guaruja – SP - Brasil

Congreso; 3 International School on Crystal Growth and Advanced Materials. V Encontro da Sociedade Brasileira de Crescimento de Cristais; 2002

Universidade do Campina

The columnar to equiaxed transition (CET) was studied in Al-2wt%Cu, Al-4wt%Cu, Al-10wt%Cu, Al-20wt%Cu and Al-33.2wt%Cu alloys, which were solidified directionally from a chill face. The main parameters analyzed include the temperature gradients, solidification velocities of the liquidus and solidus fronts, and grain size. The transition was observed to occur when the temperature gradient in the melt decreased to values – 3.89 °C/cm to 0.91 °C/cm for Al-2wt%Cu, – 0.55 °C/cm to 0.67 °C/cm for Al-4wt%Cu, – 2.05 °C/cm to 0.56 °C/cm for Al-10wt%Cu, – 2.8 °C/cm to 1.25 °C/cm for Al-20wt%Cu and – 11.41 °C/cm to 0.52 °C/cm for Al-33.2wt%Cu.  In addition, there is an increase in the velocity of the liquidus front faster than the solidus front, which increases the size of the mushy zone. The size of the equiaxed grains increase with distance from the transition, an observation that was independent of alloy composition. The results are compared with both, obtained previously in lead - tin alloys and obtained by other authors.