合金组织与性能的影响
(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 研究稀土Er含量对Sn-3.0Ag-0.5Cu无铅焊料合金显微组织以及性能的影响。结果表明：当Er含量为0.05%~0.50%(质量分数)时，对该无铅焊料合金的导电性和腐蚀性影响不大，但使熔化区间温度降低；当Er含量为0.05%时，焊点剪切强度最高；当Er含量为0.10%时，焊料铺展面积最大，焊料润湿性有所改善，同时焊料的拉伸强度达到最高；当Er含量为0.25%时，伸长率最大。随着Er含量的增加，该焊料合金的组织由树枝晶向等轴晶转变，且组织逐渐细化。Er的较佳添加量为0.05%~0.25%。
关键字: 无铅焊料；Sn-3.0Ag-0.5Cu；Er；组织；性能
Sn-3.0Ag-0.5Cu lead-free solder alloy
（School of Materials Science and Engineering, Central South University,Changsha 410083, China）
Abstract:Trace rare earth element Er was added into Sn-3.0Ag-0.5Cu solder to investigate the effect of rare earth on the microstructure and mechanical properties of SnAgCu solder. The results show that, when Er content(mass fraction) is within 0.05%−0.50%, the Er has a slight effect on the resistivity and corrosion, and lowers the melting range. When Er content is 0.05%, the shear strength is the highest. When Er content is 0.10%, the spreading area is the biggest and the tensile strength is the highest. When Er content is 0.25%, the elongation is the highest. With the increase of Er content, the microstructure of the solder changes from fir-tree crystal to equiaxed crystal and is refined. And the suitable content of Er is within 0.05%−0.25%.
Key words: lead-free solder; Sn-3.0Ag-0.5Cu; Er; microstructure; property
