Sn-Bi-X合金的形变与断裂
摘要如今无铅焊料在电子封装行业的应用越来越广泛，逐渐取代传统的 Sn-Pb 焊料。 Sn-Bi 焊料合金是主要的几大无铅焊料之一，而 Sn-Bi 焊料的延展性差，不易做成线 材使用。本文在 Sn-40Bi 合金的基础上，通过合金化方法，分别添加 In、Cu 元素， 形成 Sn-40Bi-vIn、Sn-40Bi-zCu 两个合金系列；采用光学显微镜（OM）、扫描电镜（SEM） 对合金组织进行观察；采用差示扫描量热仪（DSC）表征合金熔融特性；X-射线衍射 仪（XRD)测试合金内部晶体结构；最后在拉伸载荷作用下，改变试验温度（常温、 60℃、80℃、100℃、120℃）条件，观察系列合金在不同温度下的拉伸性能、形变与 断裂。78240
结果表明：（1）Sn-40Bi-vIn（v =1、2、4、6、8）合金随着 In 含量的增加，组织 发生粗化；Sn-40Bi-zCu（z = 0。1、0。3、0。5、0。7、1）合金随着 Cu 含量的增加，组织 发生细化；（2）Sn-40Bi-vIn 合金的熔点随着 In 含量的增加越来越低，熔程也越来越 小，添加少量的 In 能够降低 Sn-Bi 合金的熔点；（3）Sn-40Bi-vIn 合金中 In 含量相对 较高时，在温度相对低的情况下延展性较好；In 含量相对低时，在温度相对高的情况 下延展性较好；Sn-40Bi 合金添加 0。3%的 Cu 元素在 120℃温度下的延展性最好。
毕业论文关键词：无铅焊料；锡铋系合金；力学性能；显微组织；形变
Abstract Today, lead-free solder is widely used in electronic packaging industry and gradually substituting the traditional Sn-Pb solder。 Among the lead-free solders, Sn-Bi alloy is showing poor ductility, not easy to make wire。 Sn-40Bi-vIn and Sn-40Bi-zCu, this two alloy series were fabricated by doping element In and Cu with various contents respectively。 The microstructure of the two alloys were observed by optical microscope (OM) and scanning electron microscopy (SEM); Then, use Differential Scanning Calorimetry (DSC) to characterize the alloy melting behavior; Via X-ray diffraction (XRD) to test alloy internal crystal structure; Finally, the deformation and fracture behavior under tensile loadings were implemented at the different temperatures 。
The results can be concluded as following:
(1)The microstructure of Sn-40Bi-vIn（v =1、2、4、6、8）alloy may get coarsening with increasing of In content; Instead the rising Cu content in Sn-40Bi-zCu（z = 0。1、0。3、 0。5、0。7、1）alloy can refine the microstructure。
(2)With the increase of In content, the melting point of Sn-40Bi-vIn alloy is getting lower, and the melting process is getting smaller。 That is, adding a small amount of In can lower the melting point of the Sn-Bi alloy;
(3)Sn-40Bi-vIn alloy will show a better ductility at lower temperature with higher In added in; On the contrary, when the temperature is relatively high, it displays better ductile only with little In doped in。 As for the Sn-40Bi-zCu alloy, this alloy demonstrate good ductility at 120℃ with z equaling 0。3, with 0。3% Cu added in Sn-40Bi alloy。
Keywords: Lead-free solder; Sn-Bi-X alloy; Mechanical properties; Microstructure; Deformation
目 录
第一章 绪论 1
1。1 引言 1
1。2 电子封装技术概述 1
1。2。1 电子封装技术 1
1。2。2 微电子焊接技术 2
1。2。3 电子封装的分类 2
1。3。1 无铅焊料的提出 3
1。3。2 无铅焊料的技术要求