Abstract Sn-Bi-based Thermal Interface Materials (TIM) are adequate alloys to promote heat dissipation in power electronics. However, despite the necessary thermal connection, mechanical support for different components and substrates are of prime importance in microelectronic devices. In this framework, the effects of Antimony (Sb) additions on the microstructure and tensile properties of the Sn-52 wt% Bi alloy are investigated. Various Sn-Bi(-Sb) samples solidified at different cooling rates and two levels of Sb-containing alloys allow a comprehensive examination of length scales of either dendritic or eutectic microstructures. A number of experimental techniques are used here to permit a sound analyses of the ternary Sn-Bi(-Sb) alloys: transient directional solidification, optical microscopy (OM), triangle and intercept quantification methods, scanning electron microscopy (SEM), x-ray fluorescence (XRF), x-ray diffraction (XRD), tensile tests and fractography. The addition of Sb enhances the nucleation of primary dendritic trunks, which resulted in a decrease in the primary dendritic arm spacing (λ1) by about 5 times for the Sn-52 wt% Bi-2 wt% Sb alloy as compared to the results for the binary Sn-Bi alloy. The relationships found for tensile properties as a function of the secondary dendritic arm spacing (λ2) demonstrate that Sb additions increase the alloy strength while preserving the ductility. This is due to very thin SnSb intermetallic particles formed in the Sn-rich dendritic matrix. The influence of λ2 variation on both the yield and ultimate strengths is roughly insignificant while the ductility varies strongly between 14.4% and 52% for samples solidified from 0.05 °C/s to 5.0 °C/s respectively. When 2.0 wt% Sb is added, there is a maintenance in the levels of ductility as those found for the binary Sn-Bi alloy. This occurs especially for very refined dendritic and eutectic microstructures samples, which also exhibit a ductile fracture mode.

中文翻译：

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定向凝固的 Sn-52 wt% Bi-1wt% Sb 和 Sn-52wt% Bi-2wt% Sb 合金的显微组织表征和拉伸性能

摘要 Sn-Bi 基热界面材料 (TIM) 是促进电力电子设备散热的合适合金。然而，尽管有必要的热连接，但对不同组件和基板的机械支撑在微电子设备中是最重要的。在此框架中，研究了添加锑 (Sb) 对 Sn-52 wt% Bi 合金的微观结构和拉伸性能的影响。以不同冷却速率凝固的各种 Sn-Bi(-Sb) 样品和两种含 Sb 合金水平允许对枝晶或共晶微观结构的长度尺度进行全面检查。这里使用了许多实验技术来对三元 Sn-Bi(-Sb) 合金进行合理的分析：瞬态定向凝固、光学显微镜 (OM)、三角和截距量化方法，扫描电子显微镜 (SEM)、X 射线荧光 (XRF)、X 射线衍射 (XRD)、拉伸试验和断口分析。Sb 的添加增强了初级枝晶主干的成核，与 Sn-52 wt% Bi-2 wt% Sb 合金的结果相比，这导致初级枝晶臂间距 (λ1) 减小了约 5 倍二元Sn-Bi合金。拉伸性能与二次枝晶臂间距 (λ2) 之间的关系表明，添加 Sb 可提高合金强度，同时保持延展性。这是由于在富锡枝晶基质中形成了非常薄的 SnSb 金属间化合物颗粒。λ2 变化对屈服强度和极限强度的影响大致不显着，而对于从 0.05 °C/s 固化到 5 °C 的样品，延展性在 14.4% 和 52% 之间变化很大。分别为 0 °C/s。当添加 2.0 wt% Sb 时，延展性水平保持在二元 Sn-Bi 合金中。这尤其发生在非常精细的枝晶和共晶微观结构样品中，这些样品也表现出韧性断裂模式。