强磁场下Cu-25%Ag合金的凝固行为  

Investigation on Solidification Behavior of Cu-25%Ag Alloy in High-Intensity Magnetic Field

作　　者：李贵茂[1] 王恩刚[1] 张林[1] 赫冀成[1] 

机构地区：[1]东北大学材料电磁过程研究教育部重点实验室,辽宁沈阳110819

出　　处：《东北大学学报（自然科学版）》2011年第1期67-71,共5页Journal of Northeastern University(Natural Science)

基　　金：国家高技术研究发展计划项目(2007AA03Z519);高等学校学科创新引智计划项目(B07015)

摘　　要：研究了强磁场对Cu-25%Ag(质量分数)合金凝固组织的影响,分析了不同磁场条件对合金凝固组织的作用机理.研究发现,均恒磁场和梯度磁场对合金的凝固组织有重要影响,改变了富Cu枝晶形貌和尺寸,无磁场条件下初生富Cu枝晶分布不均匀,一次枝晶比较长且粗大,枝晶主要以柱状枝晶为主;在12 T磁场条件下,富Cu枝晶分布比较均匀,一次枝晶变短、粗化,枝晶主要以胞状枝晶为主;在负梯度磁场条件下,富Cu枝晶分布不均匀,在试样下部,树枝晶减少,以小平面方式生长的粗大胞晶为主.通过实验研究表明,利用均恒强磁场控制Cu-Ag合金凝固组织,细化晶粒、减小偏析是具有可行性的.The effect of high-intensity magnetic field on the solidified microstructure of the Cu-25wt%Ag was investigated,as well as the mechanism of the solidification processes of the alloy under different magnetic conditions.It is found that both the uniform magnetic field and gradient magnetic field can affect greatly the solidified structure of the alloy,such as the changes of the size and morphology of Cu-rich dendrites.The primary Cu-rich dendrites are distributed unevenly without magnetic field and they are comparatively thick and long,and most of them are in columnar shape.When the Cu-rich dendrites are in a 12 T magnetic field,they are distributed uniformly and the primary dendrites become short and thick,and most of the dendrites are in cellular shape.When the Cu-rich dendrites are in a negative gradient magnetic field,they are distributed unevenly,and the quantity of dendrites decrease at the bottom of samples where most of the dendrites are in faceted growth and thick cellular shape.Experimental results showed that the constantly uniform magnetic field is feasibly to control the solidified structure of the Cu-Ag alloy and available to grain refining and reducing segregation.

关 键 词：强磁场 CU-AG合金 富Cu枝晶 成分过冷 形核率 

分 类 号：TG335.58[金属学及工艺—金属压力加工]