Determination of the Jackson–Hunt constants of the In–In2Bi eutectic alloy based on in situ observation of its solidification dynamics Original Research Article

We present a real-time observation study of lamellar patterns in thin-sample directional solidification of a near-eutectic In–In2Bi metallic alloy. The spacing range of stability is shown to extend from about 0.9λJH to 2.2λJH, where λJH is the Jackson–Hunt minimum undercooling spacing, in agreement with what was observed earlier in transparent eutectics. We analyze the time evolution of non-uniform spacing distributions using a previously established semi-empirical “spacing-diffusion” law [Akamatsu et al., Metal. Mater. Trans. A 35 (2004) 1815]. We obtain a quantitative estimate of the Jackson–Hunt constants and other material parameters relevant to eutectic growth, among which image and D = 505 ± 75 μm2 s−1, where V is the solidification speed, and D is the solute diffusion coefficient in the liquid.