Sn基活性焊料低温钎焊5A06 Al合金接头的组织及力学性能研究

Microstructure and Properties of 5A06 Al Alloy Brazed with Sn-based Active Solders at Low Temperature

在电子装联过程中,铝合金基板较差的可焊性限制了其与电子器件间的直接低温钎焊连接。本研究分别采用Sn1Ti0.3Ga活性合金焊料和Ni-10wt%Cu合金骨架强化的Sn1Ti0.3Ga复合焊料在260℃对5A06铝合金进行了低温活性钎焊,研究了焊料成分及钎焊时间对接头显微结构和力学性能的影响。结果表明,合金焊料与复合焊料均能实现Al合金的无钎剂连接;当使用合金焊料时,焊缝中出现了因Al合金表面氧化膜剥离而形成的层状夹杂物,并且合金焊料在Al母材中发生了晶间扩散的现象;当使用复合焊料时,焊缝中形成了絮状的Al_(3)(Ni,Cu)_(2)弥散相,合金骨架表面则形成了(Cu,Ni)_(6)Sn_(5)相,且随着钎焊时间的延长弥散相逐渐被(Cu,Ni)_(6)Sn_(5)相替代。剪切测试结果表明,相较于合金焊料,使用复合焊料可获得更高的接头强度,钎焊30 min时接头强度最高,达到了31.42 MPa。

During the electronics assembly process,the direct low-temperature soldering between Al substrate and electronic devices is difficult because of the poor solderability of Al alloy.In this study,active soldering of 5A06-Al alloy was performed at 260℃ by usingSn1Ti0.3Gaalloy solder and Ni-10wt%Cualloy skeleton reinforced Sn1Ti0.3Gacomposite solder,respectively.The effects of solder compositions and soldering time on the microstructure and mechanical properties of the joints were investigated.The results show that the alloy solder and composite solder can realize the fluxless joining of Al alloy.When soldered with the alloy solder,the layered inclusions are formed in the solder seam due to the stripping of oxide film from the Al surface,and intergranular diffusion occurs in the Al substrate.When soldered with the composite solder,the Al_(3)(Ni,Cu)_(2),flocculent dispersive phase is generated in the solder seam,and the(Cu,Ni_(6)Sn_(5) phase is formed on the alloy skeleton surface;moreover,the Al_(3)(Ni,Cu)_(2) flocculent phase is gradually replaced by the(Cu,Ni_(6)Sn_(5) phase with the soldering time increasing.The shearing test results show that the joints using composite solder has higher shear strength than that using alloy solder,and the highest strength value of 31.42 MPa is obtained when soldered for 30 min.