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采用定向凝固法,研究了 Ce 和 La 对球墨铸铁石墨化的影响。Ce 和 La 在球墨铸铁中是碳化物形成元素,会提高石墨化的过冷度。所观察到的行为与铸铁中首次形核处 A 类夹杂的化学组分变化有关,A 类夹杂是石墨球的原始形核场所。铁中 Ce 和 La 含量合适时,在高过冷度下其他形核场所活化,铸铁中的球结数有一个最大值。然而,当铸铁中 Ce 和 La 过量时,则因出现大量碳化物而使球结数量锐减。
The effect of Ce and La on the graphitization of nodular cast iron was studied by directional solidification method. Ce and La are carbide-forming elements in nodular cast iron that increase the degree of undercooling of the graphitization. The observed behavior is related to the chemical composition change of the A-type inclusions in the first nucleation of the cast iron. The A-type inclusions are the original nucleation sites of graphite spheres. Iron and Ce and La content is appropriate, the other under high undercooling nucleation site activation, the cast iron in the number of nodules have a maximum. However, when Ce and La in cast iron are excessive, the number of nodules is drastically reduced due to the presence of a large amount of carbides.