Mapping erosion of MMCs at elevated temperatures: some recent advances

Studies of both room and elevated temperature erosion of MMCs have shown distinctive trends as a function of increasing reinforcement percentage, particle velocity and size, and exposure temperature. Such results have implications for selection of MMC parameters for optimization of exposure conditions. Materials selection maps have been constructed to identify the most appropriate MMC for a given set of conditions. One question which frequently arises in relation to such maps for MMCs is the extent to which variables such as particle size and velocity may be optimized for a given system at various temperatures. Such variables are critical in determining the extent of erosion resistance. However, up to now, there has been very little work carried out to investigate the separate effects of these variables on the erosion of MMCs at elevated temperatures.This paper, describes recent developments in erosion-oxidation mapping of Ni-Cr/WC MMCs following on from earlier published work, with particular emphasis on the development of materials performance maps. New mapping approaches are proposed to incorporate the effects of particle size and velocity. In addition, the results are interpreted in terms of the different mechanisms governing erosion-oxidation of the various reinforcement volume fractions at elevated temperatures.