Growth of lamellar eutectic dendrites in undercooled melts

Electromagnetic levitation was employed to undercool bulk samples of eutectic Ni 21.4 at% Si alloys. Large undercoolings were realized by containerless processing of the melts. Speeds of crystal growth were determined in relation to undercooling. The growth kinetics during solidification of the eutectic alloys was regulated by atomic diffusion. A peak in the relation of the growth speed on undercooling was noted which is caused by the progressively decreasing diffusion coefficient counteracting the improvement of the driving force of crystallization with increasing undercooling.