Evaluation of the rodlike cu6sn5 phase in directionally solidified tin — 0.9 wt.% copper eutectic alloys

Sn — 0.9 wt.% Cu alloys were directionally solidified under controlled conditions after which diameters of the aligned and rodlike Cu6Sn5 eutectic phase were measured as a function of the imposed growth velocity. A rod diameter (d) and growth velocity (V) relation of d2V = constant was found, which is analogous to that established for eutectic phase spacings. A discussion is presented for using the fiber diameter, in lieu of or in addition to the interrod spacing, to evaluate the relation between solidification processing parameters and the observed microstructure.