定向凝固速率对Cu-7.9%Co包晶合金凝固组织的影响  

Effect of Growth Rate on Directionally Solidified Microstructure of Cu-7.9%Co Peritectic Alloy

作　　者：蒋冰轮[1] 李双明[1] 刘林[1] 傅恒志[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2006年第11期1712-1715,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金项目(50395102;50401014);西北工业大学英才计划项目资助

摘　　要：对Cu-7.9%Co包晶合金不同定向凝固速率下的凝固组织进行了研究。结果表明:在定向凝固速率1μm/s^100μm/s下,随凝固速率的提高,初生α-Co相体积分数减少,使形态从定向生长的枝晶转变为等轴枝晶,相应地β-Cu包晶相的生长界面形态由平界面转变为枝状界面。利用最高界面生长温度假设,计算得到了凝固速率在0.55μm/s^5000μm/s范围内α-Co相领先于β-Cu相生长,与实验结果较为吻合;并当凝固速率大于5000μm/s时,β-Cu相的凝固界面生长温度高于α-Co而成为领先相,可以不通过包晶反应直接从熔体中凝固析出。Directionally solidified microstructures of Cu-7.9%Co peritectic alloy have bee investigated at the growth rate ranging from 1 μm/s to 100μm/s. The results show that the morphology of α-Co primary phase changes from a columnar dendrite to an equiaxed dendrite and its volume fraction decreases with increasing of growth rate. Simultaneously, the interface morphology of β-Cu peritectic phase becomes unstable from planar to dendritic interface. The theoretical analysis results indicate that α-Co phase can grow ahead of β-Cu phase as the growth rate ranges from 0.55μm/s to 5000μm/s, which is in agreement with the experimental results. In addition, when the growth rate is more than 5000 μm/s, β-Cu phase can grow as the primary phase and directly solidifies from the liquid metal without peritectic reaction.

关 键 词：Cu-7.9%Co 包晶合金 定向凝固 界面温度 

分 类 号：TG111.4[金属学及工艺—物理冶金]