Processing and properties of metal matrix composites synthesized by SHS

Self-propagating high-temperature synthesis (SHS) is a flexible process to produce novel materials with useful properties. SHS is based on highly exothermic chemical reactions between starting material powders and it can be used to produce e.g. ceramic materials, metal matrix composites (MMC), and intermetallics such as aluminides, silicides etc. This paper focuses on the near net shape MMC's produced by SHS for various applications and summarises their processing and most important properties. The process steps for production of near net shape SHS components comprise of mixing the starting material powders, green compaction of the powder to a mould, ignition of the SHS-reaction, synthesis of the material, pressure densification and controlled cooling. Machining may be performed, if e.g. high quality surface finish is needed. There are several systems that have been studied so far. In this paper we present results on composites based on TiC- reinforcements in a metal matrix. Matrixes include Ni, NiMo, NiMoCr and various commercial stainless steels and high temperature alloys. SHS MMC's have been tailored for different industrial applications, where wear and corrosion resistance is important. Because of the excellent fracture toughness of SHS materials as compared to other hard materials they have proven to be useful also for advanced armour applications