@article{oai:kansai-u.repo.nii.ac.jp:00011581,
 author = {三宅, 秀和 and 岡田, 明 and 尾崎, 良平},
 issue = {8},
 journal = {鋳物},
 month = {Oct},
 note = {Experiments were conducted to observe how nucleation and growth of primary austenite (r) of Fe-C system cast iron change with the addition of titanium (Ti) and niobium (Nb), which form carbides by reacting with carbon (C) in the melt. The results obtained were discussed both from the structural observation of carbides and thermodynamics concerning the variation of the amount of carbides formed(TiCor NbC) and the elements dissolved in the melt during cooling. The atomic concentrations of Ti and Nb in the melt were nearly equal. The degree of undercooling before nucleation and the amount of nucleation (number of austenite grains) increase by increasing the Ti content. By increasing the Ti content the growth morphology of the primary r tends to become endogeneous, i.e. the nuclei formed
over the whole area of the melt grow as equiaxed crystals. Nucleation and growth morphology are scarcely affected by the addition of Nb. Ti carbides are formed in sequence over the range from a high temperature, 1,500°C, to eutectic　temperature. Most of the Nb carbides are formed at considerably higher temeprature than liquidus and are scarcely formed at temperature near that of nucleation of the primary austenite. Consequently the amount of C atoms taken away by Ti from the melt at the liquidus is extremely larger than that by Nb. It was concluded that the factor governing the nucleation of r is not the carbides or their amount formed before the nucleation of r, but the action of the elements forming carbides while taking C out of the melt. The newly formed surfaces of the carbides are the most effective sites for nucleation, since that part is most enriched in Fe. It was also concluded that the addition of Nb hardly promotes the nucleation, because it takes little C atoms out of the melt at the nucleation temperature, while the addition of Ti promotes the nucleation by taking a large quantity of C atoms out of the melt at the nucleation temperature of the primary r.},
 pages = {486--492},
 title = {Fe-C系亜共晶鋳鉄の初晶オーステナイトの核生成に及ぼすチタン及びニオブ添加の影響},
 volume = {55},
 year = {1982}
}