Fig. 1. Quenched solid-liquid interface patterns in directionally solidified Al-4.5 wt% Cu alloy at various growth velocities: (a) 2 μm s-1; (b) 5 μm s-1; (c) 25 μm s-1; (d) 50 μm s-1; (e) 100 μm s-1; (f) 200 μm s-1.

Fig. 2. Longitudinal microstructures and corresponding texture and EBSD analysis in directionally solidified Al-4.5 wt% Cu alloy of growth velocity of 100 μm s-1: (a, b) longitudinal microstructure; (c) (100) and (110) pole figures of texture obtained from white rectangle a1 and a2; (d) EBSD map, misorientation profiles and pole figures obtained from dotted rectangle in (a).

Fig. 3. Longitudinal microstructures and corresponding texture and EBSD analysis in directionally solidified Al-4.5 wt% Cu alloy of growth velocity of 200 μm s-1: (a, b) longitudinal microstructure; (c) pole figures of texture obtained from white rectangle a1 and b1; (d) EBSD map, misorientation profiles and pole figures obtained from dotted rectangle in (b).

Fig. 4. Spacing of two tips (λ) and splitting frequency (?) vs. growth velocity for Al-4.5 wt% Cu: (a) meaning of λ and h; (b) spacing λ follows power law λ∝V-0.5; (c) splitting frequency ?.

Fig. 5. Relationship between dimensionless growth velocity and dimensionless growth direction found in Al-4.5 wt% Cu. The inset shows the illustration for the growth direction and preferred <001> direction.