摘要为了适应电子家电行业 RoHS 指令的要求，研究无铅钎料来代替锡铅钎料 变得十分的迫切。无铅钎料的研究，不只是简单地提供一个替代方案，还需要考 虑无铅钎料的力学性能、钎焊和焊接接头的可靠性，尽量使用传统钎焊设备及工 艺尽可能变化少等因素。因此，无铅钎料的研究对电子电器行业的发展意义非凡。 本文根据目前无铅钎料的发展现状，选取的两种 Ag 元素含量影响 Sn-Ag-Cu 无 铅焊料合金的组织和性能。 本文通过研究不同纯银含量 SnAgCu 无铅钎料组织 的时效过程下的力学性能，润湿性，金属界面组织演变过程来确定最好的性能的 无铅钎料组织，其中 Ag 的含量分别是 1。0% ，3。0%（质量分数）。75744

通过研究锡银铜合金的融化曲线，得出了不同银含量合金的融点不同，并得 出了其变化规律。通过观察锡银铜合金在铜片上的展开的面积，和铺展率，研究 发现了不同银含量对合金润湿性能的影响。 对实验结果分析发现钎料的融点随 着银含量的增大而减小，融化过程减短，钎料发生巨大的变化；钎料的润湿性也 随着银含量的增大而降低。综上所述，全面考虑不同银含量对力学性能、润湿性 和熔点特性的影响，认为 Sn-3。0Ag-Cu 其综合性能较好。

该论文有图 30 幅，表 5 个，参考文献 33 篇

毕业论文关键词：时效 高低温循环 力学性能 润湿性 无铅钎料

Microstructure and properties of SnAgCu lead free solder with different silver content

Abstract In order to adapt to the electronic appliance industry ROHS directive requirements of lead-free solders to replace tin lead solder  becomes  very urgent。 Study of lead-free solder, not just simply provide an alternative, also need to consider the mechanical properties of lead-free solders, brazing and welding joints can be on, try to use the traditional brazing equipment and technology changes of factors such as low as possible。 Therefore, the lead-free solder research in industrial production is of great significance。 In this paper according to the demand characteristics  and production process of lead-free solders in electronic industry development, the selection of two kinds of Ag content rang the microstructure and properties of SnAg Cu lead free solder alloy。 This paper Through the aging process of different silver content SnAgCu lead-free solder microstructure on the mechanical properties, wettability, metal interface microstructure evolution to determine  the best performance of lead-free solder organization, the Ag content is 1。0%, 3。0% (mass fraction)。Through the study of tin silver copper alloy melting curve, it is concluded that the different content of silver alloy melting point is different, and it is concluded that the variation。 Through the observation of SnAgCu alloy on the copper of  area, and spreading rate, the study found that the influence of different content of silver on the wetting properties of the alloy。 The experimental result, it is found that the solder melting point decreases with the increase of the content of silver, melting process shorter, solder occurred great changes; solder wettability also with increasing silver content decreased。 Summing up the appeal, taking full account of the different silver content on mechanical properties and effect of wetting and melting characteristics of that Sn-3。0Ag-Cu its comprehensive performance Better。This paper is a graph, a table, a reference。

Key words: Aging High temperature cycling Mechanical Properties  Wettability  Lead-free solder

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