3D TLM formulation for thermal modelling of Metal matrix composite materials for space electronics systems

This Metal matrix composites (MMCs) are finding widespread use in the automotive and aerospace industry where strength, weight, thermal conductivity and thermal expansion are important. They are a composite of an element or alloy metal bound into a `matrix' structure, formed by a reaction synthesis process. The most common material combinations are aluminum (Al) and silicon carbide (SiC). Because of their composite nature, the properties of MMCs can be tailored to suit the particular application based on the contribution of individual materials. Current applications find them in automotive, aircraft brake rotors and space electronic packaging, where toughness and dimensional stability at temperature extremes are important. Several silicon-carbide particulate (p) reinforced aluminium (SiC/Al) and graphite/ aluminium (Gr/Al), electronic packages have been space-qualified and are now flown on communication satellites and Global Positioning System satellites. The most significant problem in the space power electronic module concept is the issue of adequate thermal management and consequent electrical performance. It is believed that a Metal Matrix Composite (MMC) heat spreader, with high thermal conductivity and low CTE has the potential to solve many of these thermal management issues. Applied to electronics cooling applications, the primary advantage of MMCs is the ability to tailor the CTE to match bonded and mating materials, such as copper, braze material, ceramic substrates, and silicon in one hand and in other hand as the electronics devices get smaller and smaller, self-heating becomes important and changes the electronic performance of device. This thermal-electronic coupling effect often results in thermal runaway and hence the breakdown of the device. In this paper, an investigation of the thermal behavior of space electronics devices using a Metal Matrix Composite Materials, using the Transmission -Line-Matrix (TLM) method, is exposed. The technique has been successful in modeling various heat diffusion and mass transport problems and has proven to be efficient in terms of stability, complex geometries and the incorporation of non linear material properties. The three dimensional results show that the method has a considerable potential in small devices thermal analysis and design. The results show that the development of MMCs for use in the Space Electronics Systems thermal design is quite promising considering the superior thermal characteristics.