急冷条件下Cu-Sn合金的快速枝晶生长  

Rapid dendritic growth in melt-spun Cu-Sn alloys

作　　者：杨扬[1] 徐锦锋[1] 翟秋亚[1] 

机构地区：[1]西安理工大学材料科学与工程学院,西安710048

出　　处：《中国有色金属学报》2007年第9期1521-1526,共6页The Chinese Journal of Nonferrous Metals

基　　金：陕西省自然科学基金资助项目(2006E134;2006E120);陕西省教育厅科学研究计划资助项目(06JK220)

摘　　要：研究快速凝固Cu-xSn(x=7%,13.5%,质量分数)合金的相结构、组织形态和枝晶生长特性,将金属熔体热传导方程与Navier-Stokes方程相耦合,从理论上计算液态合金的冷却速率。结果表明:在急冷快速凝固条件下,Cu-7%Sn合金形成过饱和的单相α-Cu固溶体组织;Cu-13.5%Sn合金形成以亚稳的Cu13.7Sn相为主相、α-Cu为第二相的快速凝固组织;随着冷却速率的增大,溶质截留效应增强,合金相结构由复相向单相转变;沿垂直于辊面方向上合金的组织形态依次为近辊面细小等轴晶、中部柱状晶及自由面粗大等轴晶;增大冷却速率,晶体形态由柱状晶向等轴晶转变;在急冷快速凝固过程中,α-Cu和Cu13.7Sn相均以枝晶方式生长;随温度梯度的增大,晶体生长速率呈线性增大。The phase structure and microstructural characteristics of rapidly solidified Cu-xSn（x=7%, 13.5%, mass fraction） alloys were investigated. The cooling rate was calculated theoretically by coupling the heat conduct equation and Navier-Stokes equation. The results show that under rapid solidification condition, the single phase a-Cu solid solution is formed in Cu-7%Sn alloy. The microstructure of Cu-13.5%Sn alloy consists of main phase CUl3.7Sn and a few of a-Cu phase. With increasing cooling rate, the effect of solute trapping is enhanced, and the phase structure changes from multiphase to single-phase. The microstructures of the alloy along the direction vertical to wheel surface are characterized by fine equiaxed, columnar and coarse equiaxed grain, respectively. Both a-Cu and CUl3.7Sn phase grow in the manner of dendritic growth. With increasing temperature gradient, the growth rate of columnar crystals increases linearly.

关 键 词：Cu-Sn合金 单辊法 急冷快速凝固 晶体生长 

分 类 号：TG164.1[金属学及工艺—热处理] TG113.12[金属学及工艺—金属学]