深过冷条件下Cu-Co合金的二次液相分解与合金的凝固

Secondary liquid separation and solidification of Cu-Co alloys under deep supercooling

采用熔融玻璃深过冷技术和金相分析法 ,对Cu (10 %～ 30 % )Co合金液态深过冷条件下的二次液相分解和合金的凝固行为进行了分析。研究表明 ,由于液相分解后富Co液相的溶解度随温度下降而降低 ,使Cu原子不断从富Co液相中分解出来。如果分解出的Cu原子不能扩散到富Cu液相中 ,会在富Co液相内形成富Cu液滴。但合金凝固后富Co相中富Cu相并非都来自于二次液相分解 ,一部分是来自于富Co液相长大和富Co相选分结晶。冷却曲线的测定结果和分析显示 ,Cu Co合金液相分解后 ,富Co液相的结晶温度与合金成分和实验条件有关。富Co液滴结晶完成后发生了包晶转变。

The secondary liquid separation and solidification behaviors of Cu (10%～30%)Co alloys under deep supercooling were investigated by means of fluxing glass deep supercooling technology and metallographic analysis. The results reveal that Cu is continuously separated from Co rich liquid as temperature decreasing. If Cu atoms can not diffuse into Cu rich liquid phase, new Cu rich liquid drops will form. Not all of Cu rich phases in Co rich matrix come from the secondary liquid separation, one originates select solidifying and another result from Co rich clusters growing. The cooling curves of alloys reveal that the crystallizing temperature of Co rich phase is different with the variations of the composition and experiment condition. Peritectic reaction will occur after solidification of Co rich liquid drops. [