中文摘要：

在Zr-Ce二元稳态难混溶合金的基础上添加Co-Cu二元亚稳态难混溶合金,设计了四元（Zr_aCe_b）_（1-x）（Co_cCu_d）_x复合难混溶合金.通过热力学计算了Cu和Co在两分离液相中的分配系数,并利用OM,SEM,EDS,XRD和DTA等方法研究了相形成和组织演变的机制.结果表明,单一均匀的（Zr_aCe_b）_（1-x）（Co_cCu_d）_x合金熔体在凝固过程中发生液相分离,Co和Cu元素分别分布在富Zr和富Ce液相中,最终形成富Zr-Co和富Ce-Cu两液相.在快速凝固条件下,四元合金液-液分离形成的富Zr-Co和富Ce-Cu两液相分别发生玻璃转变,形成锆基和铈基两非晶相.实验研究与热力学分析相结合,揭示了Co与Cu原子比例和Co-Cu合金添加量以及冷却速率对双非晶相形成的影响,探索了由难混溶合金制备相分离非晶合金的方法.当Co与Cu原子比及添加量分别为4∶1和38.5%时,在熔体旋甩快速冷却条件下可以获得双相非晶合金.

英文摘要：

The liquid-liquid phase separation has been used recently to design two-glassy-phase alloys with desirable mechanical, magnetic and thermal properties. The occurrence of the liquid-liquid phase separation in the Zr-Ce binary immiscible alloys can lead to the formation of two coexistent crystalline Zr-rich and Ce-rich phases after complete solidification. In this work, a new quaternary complex alloy system （ZroCeb）（1-x）（CocCud）x was designed on the basis of the addition of metastable Co-Cu immiscible alloys in the stable Zr-Ce immiscible alloys. Distribution ratio of Co and Cu in two coexistent liquids was calculated. The mechanisms of phase formation and microstructure evolution were investigated using OM, SEM, EDS, XRD and DTA. The results show that a singlephase homogeneous melt of （ZraCeb）（1-x）（CocCud）x alloys takes place the liquid-liquid phase separation during cooling through the miscibility gap. The metal elements Co and Cu are mainly concentrated in the Zr-rich and Ce-richliquids, respectively, which results in the formation of the two coexistent Zr-Co-rich and Ce-Cu-rich liquids. It was found that the coexistent Zr-Co-rich and Ce-Cu-rich liquids undergo liquid-to-glass transition and thus form dual glassy phases under the rapid quenching, respectively. The effects of the atomic ratio of Co and Cu, the addition amount and the cooling rate on the formation of the glassy phases have been discussed in detail by combining the experimental investigation with the thermodynamic analysis. A strategy for synthesizing liquid-phase-separated metallic glasses on the basis of suitably designed immiscible alloys has been proposed. Two-glassy-phase alloys can be obtained by rapidly quenching alloy melt in which the atomic ratio of Co and Cu and the addition amount are 4：1 and 38.5%, respectively.