Au-20Sn合金的急冷制备及钎焊性能

Au-20Sn Alloys Prepared by Rapid Solidification and Their Brazing Performance

用单辊旋淬法制备了Au-20Sn合金薄带钎料,利用差示扫描量热分析(DSC)、X射线衍射分析(XRD)及场发射扫描电镜(FESEM)等方法对合金的熔化特性、相组成及显微组织进行了观察分析,并研究了与Cu、Ni基材的焊接性能。结果表明,急冷钎料合金熔化温度低于共晶点且随铜辊转速发生变化,铜辊转速越快,熔点越低,急冷合金显微组织细小均匀,棒状或卵状δ-AuSn相分布于基体组织上,晶粒尺寸可达纳米级;急冷法抑制了脆性相ζ’-Au5Sn的形成,改善了合金塑性性能;急冷钎料薄带与Cu、Ni基材表面润湿优良,在Cu基材上扩散距离更远,形成无针状组织析出的界面层;与Ni形成疏松的颗粒状IMC层;Cu基体的焊接接头抗剪强度高于Ni基体。

Rapidly quenched Au-20Sn alloy ribbons were prepared by single roller melt-spinning.Their melting characteristics,phase composition,micro-structure were characterized by DSC,XRD and FESEM.The welding capability on Cu and Ni were also investigated.The results showed that the melting point of rapidly quenched Au-20Sn alloy is lower than the eutectic melting point and depends on the rotation speed of the copper roll.The faster the roller rotation speed is,the lower the melting point is.The microstructure of the quenched alloys is fine and uniform,and the rod-shaped or ovateδ-AuSn phase is distributed on the matrix structure,and the grain size can reach the nanometer scale.The quenching method inhibits the formation of brittle phaseζ'-Au5Sn and improves the structure and mechanical properties of alloys..The solder ribbons have excellent wettability with Cu and Ni substrates,and spread farther on the Cu substrate to form an interface layer which is free of needle-like structure,and form a loose granular IMC layer with Ni..The welded joint of Cu matrix has higher shear strength than Ni matrix.This is attributed to their diffusion distance and different interface.The diffusion distance of solder on Cu is further than Ni.Uniform thickness interface is formed with Cu,while granule IMC interface is formed with Ni.