为研究机械合金化法制备Ag-Cu中温合金钎料的工艺过程,系统分析了球磨工艺参数对合金焊粉粒度及形貌演变的影响,确定了机械合金化制备球磨焊粉的优化工艺参数.采用X射线衍射仪(XRD)、扫描电镜(SEM)和差示扫描量热分析仪(DSC)等分析手段,对合金化过程中物相变化、微观结构及熔化特性进行了表征,并在此基础上进行了Ag-Cu基三元和四元焊粉机械合金化的研究.结果表明:Ag-Cu系合金焊粉经优化工艺(球料比20:1,转速400 r/min,无水乙醇作为工艺控制剂,球磨40 h)球磨后,合金化完全,以过饱和固溶体为基体相;不同组元的添加对于焊粉尺寸形貌和相结构的影响不同.Ag-Cu-10Sn粉末在球磨40 h后生成了以亚稳态的过饱和固溶体Ag(Cu)为主要组成相的合金粉,其金相组织细小均匀,与不锈钢基板之间形成过渡层,有利于增加接头强度.这表明,通过控制球磨工艺和多组元的添加,可改变合金粉末的形貌和相结构,能得到过饱和固溶体为主要组成相的钎料合金,有利于改善钎料的性能.%To study the preparation process of the medium temperature solder powders using mechanical alloying method, the effects of ball-milling parameters on the size and morphology evolution of the powders were systematic studied and optimized. The phase compositions, microstructure and melting properties of the powders were characterized by X-ray diffraction ( XRD ) , scanning electron microscopy ( SEM ) and differential scanning calorimetry (DSC) methods. The mechanical alloying of ternary and quaternary solder powders based on Ag-Cu was also carried out. The results show that Ag-Cu system solder powders can be completely alloyed with the optimized ball-milling parameters:20:1 ball-to-powder weight ratio, 400 r/min milling speed, ethyl alcohol as PCA, milling for 40 h, and the supersaturated solid solutions can be obtained. The different elements additions such as Sn, Zn, Ni have the different influence on the morphology and phase structure of the alloyed powders. Metastable Ag (Cu) supersaturated solid solution matrix was obtained for 40 h-milled AgCu10Sn. The fine microstructure of solder powders as well as the transition layer between brazing metal and stainless steel substrate are beneficial for the enhanced joint strength. It is shown that the powders morphology and phase structure could be modified by fine controlling the milling time and the additions of the multi-elements, which is helpful to form the supersaturated solid solution matrix, and thus to improve the performance of the solder powders.
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