Directional solidification of Fe-Al-Ta eutectic by electron beam floating zone melting

Fe-Al-Ta eutectic composites have been paid more attentions for high temperature application. Nevertheless, still there is a lack of research on microstructural characteristics and crystal growth mechanism of this eutectic obtained by high temperature gradient directional solidification technique. As such, Fe-Al-Ta eutectic composites were prepared by high temperature gradient electron beam floating zone melting technique in the present paper. Microstructures, solid/liquid interface morphologies and preferential orientations of the Fe-Al-Ta eutectic composites at different solidification rates were studied. Moreover, effect of interface perturbation wavelength on stability of the solid/liquid interface was calculated according to M-S theory and Kurz-Fisher model, respectively. These are consistent with the experimental results well. •Eutectic colonies are formed in Fe-Al-Ta eutectic composites.•Lamella/rod transition is caused by growth direction deviation from one to another.•Cellular solid/liquid interfaces are formed due to disturbance.•Preferential orientations at different solidification rates are not exactly same.•Phase interface is a semi-coherent interface with low interface energy.