The Near-Rapid Solidification Behavior of AA1070 Aluminum Alloy

Continuous strip casting process creates a near-rapid cooling condition. In this paper, the solidification behaviors of AA1070 alloy under near-rapid cooling condition have been investigated using the metallographic-EDX method. Although the AA1070 is a commercial pure aluminum alloy with limited amount of iron and silicon, its solidification behavior is quite complicated under the condition of near rapid solidification. When the alloy solidified under the condition of equilibrium or near-equilibrium solidification, the elements of iron and silicon segregated to the final solidification zone and formed coarse phases at the grain boundaries. With the increase in cooling rate to near-rapid cooling, some fine eutectic structures appeared at grain boundaries and inter-dentrites. Both binary eutectic of α-Al+AltFe and ternary eutectic of α-Al+AltFe(Si)+AlmFe(Si) were observed.