아공정, 공정, 과공정 조성의 Al-Cu 주조합금에서의 Y2O3 분말의 분산 거동에 대한 연구

Abstract

In this work, the dispersion behavior of Y2O3 particles in binary aluminum (Al)-copper (Cu) cast alloy was investigated with respect to Cu contents of 20 (hypoeutectic), 33 (eutectic) and 40 (hypereutectic) wt.%. In cases of hypo and hypereutectic compositions, SEM images revealed that the primary Al and θ phases were grown up at the beginning, respectively, and thereafter the eutectic phase was solidified. In addition, it was found that some of Y2O3 particles can be dispersed into the primary Al phase, but none of them are is observed inside the primary θ phase. This different dispersion behavior of Y2O3 particles is probably due to the difference in the values of specific gravity between Y2O3 particles and primary phases. At eutectic composition, Y2O3 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 Y2O3 particles are mostly dispersed into the eutectic phase in binary Al-Cu alloy system.