銲錫材料使用時可能受外力影響產生破壞且在製程與應用上常常在高溫的環境之下，本實驗主要研究銲錫材料之拉伸機械性質，探討介金屬化合物Cu6Sn5含量對Sn-xCu (x=0.3, 0.6, 1.3, 1.7, 2, 4, 6, 9)合金在常溫及高溫 (120℃及180℃)環境下以等應變速率 (7.5x10-4 s-1)做拉伸測試，以及在常溫下對Sn-xCu (x=0.3, 1.7, 4)做改變拉伸應變速率 (7.5x10-4 s-1、4.2x10-3 s-1、3.3x10-2 s-1)拉伸測試之拉伸機械性質的影響。Sn-xCu系合金的微觀組織為樹枝狀初晶β-Sn與散佈的介金屬化合物Cu6Sn5。隨Cu含量的增加，介金屬化合物Cu6Sn5含量提升且粗大，而初晶β-Sn量減少且有細化的趨勢；從DSC熱差分析結果顯示，Sn-xCu (x=0.3~9)合金組織內皆有熔點較低的共晶組成存在。
在常溫環境下做等應變速率 (7.5x10-4 s-1)之拉伸測試，隨著Cu含量增加，常溫下硬度較高的介金屬化合物Cu6Sn5含量也隨之增加且初晶β-Sn細化，造成材料的抗拉強度隨著Cu含量增加而提升；在高溫 (120℃及180℃)環境下做等應變速率 (7.5x10-4 s-1)之拉伸測試，可能因整體組織在高溫下軟化，造成整體抗拉強度降低，整體的伸長率提升，組織中熔點較低的共晶組成及初晶β-Sn軟化程度大於熔點較高的介金屬化合物Cu6Sn5，使得Cu6Sn5在高溫下對抗拉強度的貢獻不顯著。
　　常溫下對Sn-0.3Cu、Sn-1.7Cu及Sn-4Cu做改變拉伸應變速率 (7.5x10-4 s-1、4.2x10-3 s-1、3.3x10-2 s-1)之拉伸測試結果，發現應變速率越高對Sn-xCu合金之抗拉強度有提升作用，並發現Sn-4Cu在高應變速率下拉伸，有較高的降伏強度及流變應力，且從拉伸迫斷面及次表面的觀察，其斷裂面接近脆性斷裂，因此可能為其內部硬脆之介金屬化合物Cu6Sn5產生的效應。

The solder may be damaged in high temperature during the process and application. The most important of this study is in order to investigate the effect of Cu6Sn5 at different temperature and different strain rate on mechanical properties of Sn-xCu lead-free solders. The tensile test behavior of Sn-xCu lead-free solder alloys were be discussed in this study. The tensile tests of Sn-xCu (x=0.3, 0.6, 1.3, 1.7, 2, 4, 6, 9) lead-free solders would be done at different temperature (RT、120℃ and 180℃) with constant strain rate (7.5x10-4 s-1). And then, Sn-xCu (x=0.3, 1.7, 4) lead-free solders were be tested by changing strain rate (7.5x10-4 s-1、4.2x10-3 s-1、3.3x10-2 s-1) at room temperature; the relevant tensile properties were obtained.
The microstructure of the Sn-xCu alloys was composed of the primary dendritic phase (β-Sn) and the discretely distributed second phase Cu6Sn5. By the increasing of Cu content, the numbers of IMC (Cu6Sn5) were more and the primary phase β-Sn was finer.
The results of room temperature tensile of Sn-xCu lead-free solders at constant strain rate shown that the tensile strength of the Sn-xCu lead-free solders increased with the increasing of Cu6Sn5. Because of the softening of the overall microstructure of Sn-xCu alloys at high temperature (120℃ and 180℃), the tensile strength of the Sn-xCu lead-free solders decreased with the increasing of test temperature with constant strain rate. IMC (Cu6Sn5) for the tensile properties of Sn-xCu alloys at high temperature was less than at room temperature might be caused by the softening of the base phase of Sn-xCu alloys at high temperature.
The different strain rates (7.5x10-4 s-1、4.2x10-3 s-1、3.3x10-2 s-1) tensile test have obviously effect on tensile properties of Sn-xCu lead-free solders. It was found that Sn-4Cu have higher tensile strength at high strain rates than at low strain rates. The rupture type of Sn-4Cu at high strain rates tensile test could be a little brittle fractures. It might the effect of the Cu6Sn5.

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