US Egypt Cooperative Research: Development of High Performance Nano-Sized Tungsten Heavy Alloy Composites by Powder Metallurgy

这项合作研究项目由Randall M.德国圣地亚哥州立大学教授和埃及中央冶金研究与发展研究所的Sayed Farag Moustafa博士就利用新的纳米包覆技术制备铜包覆纳米钨粉用于低温净成形烧结致密化的课题进行了讨论。高比重钨合金（WHA）是在20世纪30年代开发的，用于需要高密度和定制的热和电气性能的应用，可用于电气开关设备，惯性制导系统和振动阻尼。今天，新的应用正在出现在计算机和微电子系统的散热，以及在放电加工和飞机稳定器。许多WHA成分依赖于高钨含量和由各种铁、镍、钴和铜添加物组成的基质。钨在基体中的溶解度历来是诱导液相烧结致密化所必需的。伴随致密化（在接近1500°C的温度下）的是广泛的晶粒生长。然而，一种替代方法是使用具有纳米尺寸颗粒的不溶性体系W-Cu，以诱导快速、低温烧结而不使晶粒粗化。在这次合作中，将探索广泛的科学和工程应用，包括微波封装，电接触，集成电路散热器，焊接电极和等离子喷涂电极。美国合作伙伴将负责对埃及合作伙伴制造的新型粉末进行烧结和粗化研究，埃及合作伙伴还将致力于性能和应用的合理化。该项目由美国-埃及联合基金计划资助，该计划为两国的科学家和工程师提供赠款，以进行合作研究。

This collaborative research project is being undertaken by Dr. Randall M. German, San Diego State University, and Dr. Sayed Farag Moustafa, Central Metallurgical Research and Development Institute of Egypt, on the topic of utilizing new nanoscale coating techniques to form copper coated nanoscale tungsten powders for low temperature net-shape sintering densification. Tungsten heavy alloys (WHAs) were developed in the 1930s for applications requiring high density and tailored thermal and electrical properties useful in electrical switching equipment, inertial guidance systems, and vibration dampening. Today, new applications are emerging in computer and microelectronic systems for heat dissipation, as well as in electro-discharge machining and aircraft stabilizers. Many WHA compositions rely on high tungsten contents and a matrix consisting of various iron, nickel, cobalt, and copper additions. Tungsten solubility in the matrix is historically required to induce liquid phase sintering densification. Concomitant with densification (at temperatures near 1500°C) is extensive grain growth. However, an alternative is to use an insoluble system, W-Cu, with a nano-sized particle to induce rapid, lower temperature sintering without grain coarsening. In this collaboration, a wide range of scientific and engineering applications will be explored, including microwave packaging, electrical contacts, integrated circuit heat sinks, welding electrodes, and plasma spray electrodes. The US partner will be responsible for sintering and coarsening studies on the novel powders fabricated by the Egyptian partner, who will also work on rationalization of the properties and applications. The project is funded under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to undertake cooperative research.