Abstract

This paper is concerned with theoretical analysis of the quasi-equilibrium directional crystallization of three-component melts. How the phase composition changes at each site of the sample and how the phase compositions change for various types of phase reactions are considered. It is shown that the eutectic reaction can change to a peritectic reaction as temperature lowers during directional crystallization. A 29.96 Fe + 21.55 Cu + 2.01 Ni + 46.49 S (at %) melt was directionally crystallized. Since nickel is present in the ingot in the form of impurities dissolved in the phases of the Cu–Fe–S system, the behavior of the melt belonging to this three-component system could be involved in data interpretation. As a result, a sample has been obtained with three zones changing one another: single-phase Fe_zS_{1 ± δ} (Poss), a Poss + (Cu,Fe)_{1 + x}S (Iss) two-phase eutectic mixture, and then single-phase Iss. The average composition of the solid phase changes from one discrete value to another in going to the next zone, while the melt and solid solutions in the neighboring zones have their compositions changing continuously. These results are consistent with theoretical ideas.

中文翻译：

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通过熔体定向结晶测定 Cu(Ni)-Fe-S 体系中的共晶到包晶折叠转变

摘要

本文主要研究三组分熔体准平衡定向结晶的理论分析。考虑样品每个位置的相组成如何变化以及各种类型的相反应的相组成如何变化。结果表明，定向结晶过程中，随着温度的降低，共晶反应可以转变为包晶反应。29.96 Fe + 21.55 Cu + 2.01 Ni + 46.49 S（at%）熔体定向结晶。由于镍以溶解在 Cu-Fe-S 系统相中的杂质的形式存在于锭中，因此属于该三组分系统的熔体的行为可能涉及数据解释。结果，获得了三个区域相互变化的样品：单相 Fe _z S _{1 ± δ} ( Poss )、Poss + (Cu,Fe) _{1 + x} S ( Iss ) 两相共晶混合物，然后是单相Iss。在进入下一个区域时，固相的平均组成从一个离散值变为另一个离散值，而相邻区域中的熔体和固溶体的组成连续变化。这些结果与理论想法是一致的。