Investigation of the Effect of Rare-earth Element Ce on Graphite Spheroidization

Thermal analysis test was adopted to investigate the effects of rare-earth element Ce on the degree of undercooling and the morphology of graphite growth during the solidification process of the hypereutectic Ni-C alloy.It is indicated that Ce addition significantly increases degree of undercooling of primary graphite,and the morphology of graphite changes from flake to sphere.However,if a small undercooling is given,the graphite grows in flake form after adding Ce.The experiment result shows that undercooling is a primary factor that promotes graphite to grow in spherical form during the solidification,and rare-earth element Ce is not sufficient condition for graphite spheroidization.