Controlled Solidification of Eutectic Cast Iron

Abstract

Eutectic Fe-C, Ni-C and Fe-C-Si alloys have been solidified directionally in an electron-beam floating zone apparatus under carefully controlled conditions and the resulting morphologies in these alloy systems have been studied as a function of rate. In addition, the transition from the stable iron-graphite (grey iron) to the metastable iron-iron carbide (white iron) mode has been observed and has been related to the iron-carbon/iron-iron carbide double phase diagram by means of undercooling measurements. Interlamellar spacing measurements carried out on both the graphitic and carbidic modes using material of the same composition and purity under identical experimental conditions showed a λaR-1/2 and a λaR-1/3 relationship in the iron-graphite and iron-iron carbide eutectic systems, respectively.