Sn-1.0Ag-0.5Cu-0.06Sm无铅钎料的蠕变性能研究

Creep Behavior of Sn-1.0Ag-0.5Cu-0.06Sm Lead-free Solder

通过机械混合法制备了Sn-1.0Ag-0.5Cu-0.06Sm无铅复合钎料,采用SEM、EDS以及结合强度测试仪研究了蠕变对Cu/Sn1.0Ag0.5Cu-0.06Sm/Cu焊点的基体组织、界面形貌和力学性能的影响。结果表明,在长时间的高温蠕变作用下,焊点基体组织中不断析出Ag3Sn相和Cu_(6)Sn_(5)相,且合并长大聚集粗化;IMC层的形貌从回流态时的扇贝状不断生长为较为平直的宽厚层状,由Cu_(6)Sn_(5)单相转变为Cu_(6)Sn_(5)和Cu_(3)Sn两相,这导致焊点的抗拉强度比回流态时下降了21.3%。

Sn-1.0 Ag-0.5 Cu-0.06 Sm lead-free composite solders were prepared by mechanically mixing method.The effects of creep on the matrix microstructure and interface morphology as well as mechanical properties of Cu/Sn-1.0 Ag-0.5 Cu-0.06 Sm/Cu solder joints were investigated by SEM,EDS and bond strength tester.The results reveal that under the action of long-term high temperature creep,Ag3Sn and Cu_(6)Sn_(5) phases can be continuously precipitated in the matrix structure of the solder joints,which is merged,grown and aggregated.The morphology of the IMC layer continuously is grown from a scallop shape in the reflow state to a relatively flat and thick layer,and transformed from Cu_(6)Sn_(5) single phase to two phases of Cu_(6)Sn_(5) and Cu_(3)Sn,resulting in decrease of 21.3%in the tensile strength of the solder joint compared with that of the reflux state.