Al-6.6 wt. pct. Si-0.6 wt. pct. Mg 合金을 相違한 凝固條件으로 一方向凝固시켜 組織, dendrite cell의 크기 및 機械的性質을 調査하였다. 柱狀晶에서 等軸晶으로의 遷移는 溫度勾配(G)와 凝固速度(R)의 比, G/R이 一定値 未滿일 때 일어났다. 凝固條件에 따른 dendrite cell의 크기를 調査하였던바 그 크기는 冷却速度의 大略 -1/4乘에 比例했고, 또한 local solidification time의 大略 0.22乘에 比例했다. 引張强度는 dendrite cell의 크기가 작을수록 增加했고, 冷却速度가 커질수록 增加하였다.

Metallographic structure, dendrite cell size and mechanical properties of Al-6.6 wt. pct. Si-0.6 wt. pct. Mg alloy, unidirectionally solidified under various solidification conditions, have been studied. It has been found that the transition from columnar to equiaxed structure occurs when the ratio of temperature gradient (G) to rate of solidification (R), G/R, is smaller than a constant value. Dendrite cell size has been measured to be proportional to the negative one-fourth power of the cooling rate, and has been also measured to be proportional to the 0.22 power of local solidification time. Tensile strength increases as the dendrite cell size decreases and the cooling rate increases.