Phase Equilibria on Fe-Cu Based Alloys Used for Electrically Conductive Materials

众所周知，许多Fe-Cu基合金在液相中具有宽的相分离间隙，并且通过利用这种相分离，一些Fe-Cu基合金被用作导电材料和软磁材料，其中细小的富Cu相沉淀在铁基体上。Fe-Cu-Si和Fe-Cu-P是此类合金系统的典型实例。Fe-Cu-Si和Fe-Cu-P三元合金也是近年来发展起来的在焚烧灰重熔过程中形成的基本合金体系。此外，了解Fe-Cu系的热力学性质对废钢重熔除铜具有重要意义。尽管如此重要，Fe-Cu基三元合金的相图还没有很好地建立。本文的目的是建立Fe-Cu-Si和Fe-Cu-P三元合金的相图和热力学性质。1995年，在1250 ~ 1550 ℃温度范围内，测定了Fe-Cu-Si系中FeSi化合物的溶解度、固态Si在液相中的溶解度以及两个不互溶液相之间的联系线。采用固液扩散偶技术测定了1250 ℃下Fe-Cu-P系固体铁与富铜熔体之间的结合线。测定的Fe-Cu-P体系的相平衡也与文献相图不同。基于亚规则溶液模型，对Fe-Cu-Si和Fe-Cu-P体系相图进行了解析计算。

It is known that many Fe-Cu based alloys have wide miscibility gap in liquid phase, and by utilizing such phase separation some Fe-Cu based alloys are used as an electrically conductive and a soft-magnetic materials in which fine Cu-rich phase precipitates on iron matrix. Fe-Cu-Si and Fe-Cu-P are typical examples of such alloy systems. Fe-Cu-Si and Fe-Cu-P ternaries are also basic alloy systems formed in the remelting process of incinerated ash which is recently being developed. Moreover, it is important to understand thermodynamic properties of Fe-Cu system to remove copper from remelted steel scrap. In spite of such importance, phase diagrams of Fe-Cu based ternary alloys are not well established. The objective of the present work is to establish phase diagrams and thermodynamic properties of Fe-Cu-Si and Fe-Cu-P ternary alloys. In 1995, solubility of FeSi compound, solid Si in liquid phase and tie lines between two immiscible liquid phases in Fe-Cu-Si system have been measured in the temperature range from 1250ﾟC to 1550ﾟC.As the results, observed phase equilibria differed from the literature phase diagram proposed by Chang et al. In 1996, tie lines between solid iron and copper-rich melt in Fe-Cu-P system were determined at 1250ﾟC by solid-liquid diffusion couple technique. Measured phase equilibria of Fe-Cu-P system also differed from the literature phase diagram. Phase diagrams of Fe-Cu-Si and Fe-Cu-P systems were thermodynamically assessed based on the sub-regular solution model.