铸态下Sn-Bi二元共晶焊料合金的组织特征及其力学性能  

Microstructure and Mechanical Properties of As-cast Sn-Bi Eutectic Solder Alloys

作　　者：唐玲[1] 张会[1] 孟凡莹[1] 刘艳[1] TANG Ling;ZHANG Hui;MENG Fanying;LIU Yan(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723003,China)

机构地区：[1]陕西理工大学材料科学与工程学院,陕西汉中723003

出　　处：《有色金属工程》2024年第7期52-59,共8页Nonferrous Metals Engineering

基　　金：陕西省科技厅科研基金项目(2024GX-YBXM-376)。

摘　　要：研究了四种不同Bi含量(45%、50%、55%、60%)的Sn-Bi二元共晶合金自由凝固下的组织特征和力学性能,探讨了Sn-Bi二元共晶合金的晶体生长机制以及Bi元素含量对合金显微组织的影响。结果表明:Sn-Bi二元亚共晶合金铸态下的金相组织为初生Sn固溶体相和Sn/Bi共晶层片集群构成,随着Bi含量的增加,呈树枝晶形态生长的初生Sn相数量减少,形态长大。初生Sn固溶体相内部脱溶析出大量的杆状或点状Bi相,形成杆状共晶结构;Sn-Bi二元过共晶合金铸态下的金相组织为初生Bi相和Sn/Bi共晶层片集群构成,初生Bi相中基本不固溶Sn元素,呈小平面方式生长,并在在初生Bi相周围包裹生长一层Sn晕圈相。在室温下,Sn-Bi二元共晶合金的硬度和强度随着Bi含量的增加而上升,延伸率随着Bi含量的增加先上升后下降。The microstructure and mechanical properties of Sn-Bi eutectic alloys with four different Bi compositions(45%,50%,55%and 60%)were studied under free solidification.The crystal growth mechanism of Sn-Bi eutectic alloys and the effect of Bi content on the microstructure of the alloy were investigated.The results showed that the microstructure of as-cast Sn-Bi eutectic alloys consists of primary solid solution phase of Sn and clusters of Sn/Bi eutectic lamellae.With increasing Bi content,the quantity of primary Sn phase with dendritic growth morphology decreased,while its size increased.A large amount of rod-like or dot-like Bi phase precipitated from the solid solution phase of primary Sn,forming a rod-like eutectic structure.The as-cast microstructure of Sn-Bi hypereutectic alloys consists of primary Bi phase and clusters of Sn/Bi eutectic lamellae.The primary Bi phase does not dissolve Sn elements,and it grows in a small plate-like manner,surrounded by a layer of Sn halo phase.At room temperature,the hardness and strength of Sn-Bi eutectic alloys increase with increasing Bi content,while the elongation first increases and then decreases with increasing Bi content.

关 键 词：Sn-Bi二元共晶合金 杆状共晶 晕圈相 显微组织 力学性能 

分 类 号：TB333.1[一般工业技术—材料科学与工程]