Abstract

In this work, the dispersion behavior of Y_2O_3 particles in binary aluminum (Al)-copper (Cu) cast alloy was investigated with respect to Cu contents of 20 (hypoeutertic), 33 (eutectic) and 40 (hypereutectic) wt.%. In cases of hypo and hypereutectic compositions, SEM images revealed that the primary Al and theta phases were grown up at the beginning, respectively, and thereafter the eutectic phase was solidified. In addition, it was found that some of Y_2O_3 particles can be dispersed into the primary Al phase, but none of them are is observed inside the primary 6 phase. This different dispersion behavior of Y_2O_3 particles is probably due to the difference in the val- ues of specific gravity between Y_2O_3 particles and primary phases. At eutectic composition, Y_2O_3 particles were well dispersed in the matrix since there is few primary phases acting as an impediment site for particle dispersion during solidification. Based on the experimental results, it is concluded that Y_2O_3 particles are mostly dispersed into the eutectic phase in binary Al-Cu alloy system.

• Keywords: Dispersion behavior;Y_2O_3 particles;Al-Cu cast alloy;Primary phase;Specific gravity;;