Band Structure Formation Mechanism in Directionally Solidified Al-38.5%Cu Alloy

The formation mechanism of the band structure formed during the alternative growth of single phase Al2Cu and eutectic phase Al/Al2Cu in solidified microstructure of Al-38.5% Cu alloy was studied when the growth rate was 1 μm·s-1 and the temperature gradient was 260 K·cm-1 in liquid.The results show that the formation of band structure was related to the solute distribution ahead of solid-liquid interface due to the changes of the growth rate and alloy composition during directional solidification.With the increase of the liquid solute content of the single phase,the solidification rate of the alloy decreased,but in the growth of coupled eutectic phase the solidification rate increased.