PMC

(a) Growth front of a eutectic mixture of borneol (faceted minor constituent) and succinonitrile. Reproduced with permission from Wiley Verlag. (b) Quenched growth front of an Al-12.7 wt%Si eutectic, where an envelope of Al encloses the faceted Si crystals. According to Hellawell, this metallic ‘skin' could not have been present at temperature and must have formed during the quench. Reproduced with permission from Elsevier. (c) Growth front of an Al-51.6 wt%Ge, this work. The eutectic grows from the Al₂O₃ oxide skin (not pictured) into the melt. The solid–liquid interfaces in c share some semblance to that of (a) in that the faceted Ge phase (orange) leads at the growth front. Scale bar, 12 μm (a), 35 μm (b) and 40 μm (c).

SEM micrographs of Al-5 wt.%Si with either Eu (a–c) or Yb (d–f) additions. (a) Coral-like eutectic phase and pre-eutectic coarse Al₂Si₂Eu intermetallics; (b,c) smaller Al₂Si₂Eu intermetallic phases formed during eutectic growth. (d) Refined structure resembling the plate-like eutectic phase of unmodified alloys and coarse Al₂Si₂Yb intermetallics; (e,f) smaller intermetallic phases forming during eutectic growth.

Correlation between solute tolerances of D. hansenii and the eutectic points of those solutes. (a) Comparison between solute tolerances of D. hansenii and eutectic concentrations as well as eutectic temperatures. It appears that the lower the eutectic freezing point of a solute the greater the discrepancy between eutectic concentration and solute tolerance of D. hansenii. (b) Logarithmic correlation between solute tolerances (total ion concentrations) of D. hansenii and eutectic temperatures of the investigated inorganic salts (excluding those that enabled growth at saturation concentrations at 25 °C).

Comparison of the present model with the LZ model for prediction of the eutectic growth kinetics of an α-Ni/Ni₃Sn eutectic dendrite. The prediction of the LZ model is taken from Yang & Gao []. Experimental data measured by Yang et al. [] are also shown (filled circles). (a) Eutectic growth velocity V; (b) interlamellar spacing λ; (c) dendritic tip radius R; (d) ratio of R/λ.