Thermal conductivity effects on steady state propagation speed during self-propagating high-temperature synthesis of Ti + C green compacts

Abstract

Thermal conductivities of mixtures of titanium (Ti) and graphite (C) powder compacts are experimentally investigated and the results are presented. These compacts are used in self-propagating high-temperature synthesis (SHS) of refractory, ceramic, and composite materials. Thermal conductivity values of these compacts are important for accurate modeling of the SHS process. Results show that, thermal conductivities of the compacts increase for an increase in initial density, but decrease with an increase of Ti/C mixture ratios. The experimental results also show the dependency trend of thermal conductivity on particle size of the constituents. A numerical model was also developed to predict the steady state propagation speed along a vertical cylindrical compact employing Kanury kinetic model. An important dimensionless parameter, the Damkohler number was introduced. The effects of the variation of thermal conductivity on propagation speed due to the changes in initial density and composition mixture ratio are also presented.