三元Co-Cu-Si合金的液相分离与组织特征  

Phase Separation and Morphology Formation of Co-Cu-Si Ternary Alloy

作　　者：原建琦[1] 代富平[1] 阮莹[1] 魏炳波[1] 

机构地区：[1]西北工业大学应用物理系,陕西西安710072

出　　处：《西北工业大学学报》2008年第3期314-320,共7页Journal of Northwestern Polytechnical University

基　　金：国家自然科学基金(50121101;50395105);西北工业大学青年科技基金(W016223)资助

摘　　要：在自由落体条件下实现了三元Co45Cu45Si10和Co25Cu25Si50合金的快速凝固,所获得的最大过冷度分别为357 K(0.22TL)和320 K(0.20TL),测定其液相面温度分别为1 600 K和1 592 K,固相面温度分别为1 358 K和1 105 K。Co45Cu45Si10合金液相分离临界过冷度仅为8 K。直径大于100μm的合金液滴发生L+α-Co→ε-Co的包晶转变,凝固组织由(Cu)、ε-Co和α-Co三相组成,而直径小于100μm时,合金液滴的凝固组织主要由(Cu)和ε-Co两相组成。Co25Cu25Si50合金不存在液相分离临界过冷度,形成由CoSi、CoSi2和Cu3Si 3个金属间化合物相组成的快速凝固组织。尽管Cu3Si的形核率最大,但始终没有形成领先生长相。当过冷度小于127 K时,形成以CoSi2为初生相枝晶的凝固组织;当过冷度大于127 K时,则形成以CoSi为初生相枝晶的凝固组织。The rapid solidification of Co45Cu45Si10 and Co25Cu25Si50 ternary alloys under free fall is achieved. The experimental undercooling of Co45Cu45Si10 nd Co25Cu25Si50 alloys is up to 357 K（0. 22TL） and 320 K （0. 20TL）, respectively. The liquidus temperature of Co45Cu45Si10 and Co25Cu25Si50 alloys is determined as 1 600 K and 1 592 K, and the solidus temperature of Co45Cu45Si10 and Co25Cu25Si50 alloys is determined as 1 358 K and 1 105 K, respectively. The critical undercooling of liquid phase separation of Co45Cu45Si10 ternary alloy is only 8K. The L＋α-Co→εCo peritectic transformation takes place during metal droplets whose diameters are larger than 100μm, and solidified microstructure is composed of （Cu）, ε-Co and α-Co phases. If the diameter of alloy droplet is smaller than 100 μm, the solidified microstructure is mainly composed of （Cu） and ε-Co phases. The critical separation undercooling does not exist in Co25Cu25Si50 ternary alloy melt, and no phase separation microstructure is found in this alloy. The rapid solidification microstructure of Co25Cu25Si50 alloy is composed of CoSi, CoSi2 and Cu3Si three intermetallic compounds. Though nucleation rate of Cu3Si phase is maximal, it never acts as the leading phase. When △T〈127 K, the primary phase is dendritic of CoSi2 phase. Once △T〉127 K, the primary phase changes to the dendritic of CoSi phase.

关 键 词：落管 三元合金 液相分离 金属间化合物 快速凝固 

分 类 号：TG113[金属学及工艺—物理冶金]