Nanostructured high performance metal matrix composites for high temperature, load, wear and corrosion applications

近年来，纳米结构陶瓷-金属复合材料比传统复合材料具有更高的耐温、耐载荷、耐磨、耐腐蚀等性能。然而，由于纳米粒子在热加工过程中的粗化和溶解，以及成本的提高，这些材料在技术上无法成功。因此，拟议的研究计划旨在开发基于纳米技术和弥散强化的高性能和低成本的复合材料和涂料。将开发在相对低熔点的金属基质中具有热稳定性纳米陶瓷颗粒的粉末。这种结合，加上相对较低的加工温度，将确保最大限度地减少甚至消除纳米颗粒的粗化和溶解。将使用高能机械合金化(MA)。MA将传统的微米级陶瓷粉末粉碎到纳米级，并在较低的温度下迫使它们同时进入金属基质。生产的粉末中的一部分将用于开发超音速火焰喷涂涂层。在超音速火焰喷涂过程中，氧气和燃料的燃烧能够加热半熔融的粉末颗粒并将其投射到基材表面以形成涂层。另一部分粉末将用于粉末冶金的复合材料和部件的开发，包括压制和烧结。重点介绍了陶瓷含量低于2%B.W.(按重量计)将是铝、银、铜、铬及其合金的强化，用于要求导电性和耐高温的应用。潜在的应用包括固体氧化物燃料电池(SOFC)的互连以及中高压触点和开关。陶瓷含量大于50%的复合材料。将目标对准受强烈磨损的部件。潜在的应用是油泵的密封件和阀门，以及燃气轮机和反应堆的部件。加拿大将受益于部件的更高性能，以及机器和设备的磨损和故障损害、停机时间和维护成本的减少，特别是对关键能源行业而言。

The potential of nanostructured ceramic-metal composites to possess higher resistance to temperature, load, wear and corrosion compared to conventional composites has been proven in the past years. However, these materials could not succeed technologically because of the coarsening and dissolution of nano-particles during thermal processes and elevated cost. The proposed research program therefore aims at developing high performance and low cost composite materials and coatings based on nanotechnology and dispersion strengthening. Powders with thermally stable ceramic nano-particles in a relatively low melting metal matrix will be developed. This combination, together with relatively low processing temperatures, will insure minimisation or even elimination of nano-particle coarsening and dissolution. High energy Mechanical Alloying (MA) will be used. MA crushes conventional micro-size ceramic powders down to nano-size and forces them simultaneously into the metal matrix at a low temperature. One fraction of the produced powders will be used to develop coatings by HVOF thermal spraying. During HVOF spraying, combustion of oxygen and fuel enables heating and projecting semi-molten powder particles onto the substrate surface to create a coating. The other powder fraction will be used to develop composite materials and components by powder metallurgy, which consists of compacting and sintering. The emphasis for composites with ceramic fractions below 2% b.w. (by weight) will be the strengthening of aluminium, silver, copper, chromium and their alloys for applications requiring electrical conductivity and resistance to high temperature. Potential applications include interconnects for Solid Oxide Fuel Cells (SOFC) as well as medium and high voltage contacts and switches. Composites with ceramic fractions above 50% b.w. will target components subjected to strong wear. Potential applications are seals and valves for oil pumps, as well as components for gas turbines and reactors. Canada will benefit from the higher performance of components and from the reduction of wear and failure damage, downtime and maintenance costs of machines and equipment, especially for key energy industries.