Metastable liquid separation in undercooled Fe-Cu and Fe-Cu-Si melts containing a small B concentration and their solidification structure

Undercooling of various Fe-Cu-(Si) alloys with a small amount of B was examined. The temperature change during the static undercooling experiment was analyzed. The temperature curve showed significant undercooling. The melt was undercooled below the metastable liquid miscibility gap. In these samples, two melts separation was observed. The addition of B was effective for two melts separation. By rapid solidification of ternary Fe-Cu-B alloys, relatively uniform structure composed of iron rich droplets in copper rich matrix or copper rich droplets in iron rich matrix was formed depending on the composition. In the case of a rapidly solidified Fe-Cu-Si-B alloy, the egg-type structure was formed and some of the iron rich phase was amorphous.