Nanoscale Exploratory Research: Dispersion of Nanopowders in Solidifying Molten Metals and Formation of High-Strength Nano-Composite Solders

纳米探索性研究：纳米粉末在凝固熔融金属中的分散和高强度纳米复合焊料的形成

• 批准号: 0103159
• 负责人: Guo-Xiang Wang
• 金额: $ 9.86万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-15 至 2003-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0103159&HistoricalAwards=false
• 关键词: Nanoscale; Exploratory; Research; Dispersion; Nanopowders

This Nanoscale Exploratory Research (NER) project is an exploratory study aimed at understanding the key physical mechanisms governing the dispersion of nano-particles in molten metals and the concomitant solidification of the nano-particle-reinforced molten metals resulting in the formation of nano-particle reinforced composite solders having attractive combinations of strength, durability and reliability. Carefully orchestrated and planned experiments will be performed to produce nano-particle reinforced composite solders based on commercial tin-lead and lead-free solder mixtures blended well with nanopowders. In the first phase of this research nanopowders of copper, iron, molybdenum and nickel will be chosen and in the follow phase nanopowders of titanium dioxide and aluminum oxide will be the candidates. Innovative techniques will be developed after several trial and error experimentation to establish an efficient means for blending the nano-powders with the micron-size powders of the solder resulting in a molten solder mixture having a near uniform dispersion of nanoparticles. Quantitative measurements will be conducted to characterize the dynamics of solidification of the composite molten solder mixture. Metallurgical observations using both optical microscopy and scanning electron microscopy will be made to characterize the nature, morphology and distribution of intrinsic microstructural features and the presence and distribution of artifacts such as micro and macro porosity, voids and microscopic cracks. Mechanical tests, to include microhardness, tensile deformation and cyclic fatigue, will be conducted to demonstrate the overall superiority combination of mechanical properties of the nano-particle reinforced composite solders. It is anticipated that the findings of this research study will provide a viable solution to engineering high strength materials by adding trace amounts of nanopowders into a solidifying molten metal to form nano-particle reinforced composite. The engineered composite solders will have attractive combinations of strength; damage tolerance and durability coupled with improved reliability thereby enhancing the probability of its use on in a spectrum of microelectronic and opto-electronic devices and assemblies. Results of this research exercise will also have far reaching consequences beyond soldering materials. It is expected that the study would also shed light on several fundamental issues related to the formation of nanoparticle-reinforced metallic and even non-metallic composites. A study of the influence of nano-particles on crystalline nucleation kinetics and microstructural development will contribute to enhancing our understanding of modern solidification theory.

该纳米级探索性研究（NER）项目是一项探索性研究，旨在了解纳米颗粒在熔融金属中分散的关键物理机制，以及纳米颗粒增强熔融金属的伴随固化，从而形成具有强度，耐用性和可靠性的纳米颗粒增强复合焊料。 将进行精心策划和计划的实验，以生产基于商业锡铅和无铅焊料混合物以及与纳米粉末混合的纳米颗粒增强复合焊料。 在本研究的第一阶段中，将选择铜、铁、钼和镍的纳米粉末，并且在随后的阶段中，将选择二氧化钛和氧化铝的纳米粉末。经过多次反复试验，将开发出创新技术，以建立一种有效的方法，用于将纳米粉末与焊料的微米尺寸粉末混合，从而产生具有近乎均匀分散的纳米颗粒的熔融焊料混合物。 将进行定量测量以表征复合熔融焊料混合物的固化动力学。 将使用光学显微镜和扫描电子显微镜进行冶金观察，以表征内在微观结构特征的性质、形态和分布，以及微观和宏观孔隙、空隙和微观裂纹等伪影的存在和分布。 将进行包括显微硬度、拉伸变形和循环疲劳在内的机械测试，以证明纳米颗粒增强复合焊料的机械性能的整体优越性组合。预计这项研究的结果将提供一个可行的解决方案，工程高强度材料，通过添加微量的纳米粉末到固化熔融金属，形成纳米颗粒增强复合材料。 工程复合焊料将具有强度、损伤容限和耐久性的有吸引力的组合以及改进的可靠性，从而提高其在微电子和光电器件和组件的范围中使用的可能性。这项研究工作的结果也将产生深远的影响，超出焊接材料。 预计该研究还将揭示与纳米颗粒增强金属甚至非金属复合材料形成相关的几个基本问题。 研究纳米颗粒对结晶形核动力学和微观组织发展的影响将有助于加深我们对现代凝固理论的理解。