Sn-Sb-Cu-Ni焊料和焊点在低温条件下组织和性能研究  

Research on Microstructure and Properties of Sn-Sb-Cu-Ni Solder and Its Joints at Low Temperature

作　　者：陈海燕[1] 曾键波 谢羽 路美秀[3] 牛艳[1] 李霞[4] 

机构地区：[1]广东工业大学材料与能源学院,广州510006 [2]广州帝特电子科技有限公司,广州510545 [3]广东外语外贸大学思科信息学院,广州510006 [4]广东石油化工学院化工与环境工程学院,广东茂名525000

出　　处：《材料工程》2015年第11期57-64,共8页Journal of Materials Engineering

基　　金：广东省中国科学院全面战略合作专项资助项目(2013B91500033);广东省科技计划项目(2013B021100020);广东外语外贸大学校级青年联合基金项目(12s10);广东省公益研究与能力建设项目(2015A010105026)

摘　　要：为保证Sn-Sb-Cu-Ni合金及焊点在低温环境下使用可靠性,将SnSb 4.5CuNi合金焊料和焊点在25,-10,-20,-60℃恒温环境中进行储存565天后,考察了不同温度下SnSb 4.5CuNi合金微观组织形貌、物相、密度、电导率、抗拉强度和塑性的变化,通过纳米压痕法测量SnSb 4.5CuNi/Cu焊点界面过渡层Cu6Sn5金属间化合物(IMC)的硬度和弹性模量,对焊接接头进行抗拉强度、剪切强度和低周疲劳测试。结果表明:合金主要由SbSn和β-Sn组成,低温处理565天后合金组织形貌逐渐转变为树枝状组织,焊料合金的密度和电导率均随温度降低而升高,表明经低温储存后合金没有发生灰锡转变,但脆性SbSn相析出量的增多和枝晶组织致使铸态合金的拉伸强度降低,增加了合金脆断风险;随着温度的下降,焊接界面IMC层的弹性模量和硬度增大,焊件拉伸破坏模式从焊料内部转为IMC层,断口越趋平整,焊件的抗拉强度、抗剪强度下降,呈现了低温脆性断裂的倾向。To study the reliability at low temperature, the SnSb4.5CuNi solder and its welded joints were kept in the constant environments of 25, -- 10, --20 and --60℃ for 565 days, which offered conditions to observe and study the morphology, phase, density and electrical conductivity changes of SnSb4.5CuNi alloy microstructure at different temperatures. The nanoindentation was applied to measure the hardness and elastic modulus of the intermetallie compound （IMC）. The tensile strength, shear strength and the low cycle fatigue properties of the welded joints were tested. The results show that under low temperature condition for 565 days the solder is mainly composed of SbSn and β-Sn, the morphology turns to dendritic structure with definite orientation. The density and conductivity of the solder alloy increases with the temperature decreasing. It shows that no tin pest occurs in SnSb 4.5 CuNi solder after low temperature storage, but the SbSn phase precipitation increasing and the dendrite structure lead to decreasing of the tensile strength of the as cast alloys, and increasing of the rick of the alloy brittle fracture. With the decrease of temperature, hardness and elastic modulus of IMC layer at the interface increase and the tensile failure mode of fractures in SnSb 4.5CuNi/Cu inter-face is moving from the solder to the IMC layer, the fracture tends to be more flat, the tensile strength shear strength are reduced, and shows trend of low temperature brittle fracture.

关 键 词：无铅焊料 显微组织 低温脆性 纳米压痕测试 低周疲劳 

分 类 号：TG425.2[金属学及工艺—焊接]