Formation of Ti5Si3 by Combustion Synthesis in a Self-Propagating Mode: Experimental Study and Numerical Simulation

Abstract

AbstractTitanium silicide (Ti5Si3) was fabricated by self-propagating high-temperature synthesis (SHS) from the elemental powder compact. With the increase of sample density from 50 to 60% TMD, experiments showed that the flame-front velocity increased from 28 to 50 mm/s and combustion temperature from 1,580 to 1,700°C. Based on their dependence, the activation energy of the synthesis reaction, Ea=193 kJ/mol, was deduced. By numerical simulation of combustion wave kinetics, the Arrhenius factor of the rate function, K0=3×109 s−1, was determined for the 5Ti + 3Si reaction system. The effect of sample compaction density on the SHS process was correlated to the variation of the effective thermal conductivity (keff) of the powder compact. The ratio of keff/kbulk=0.02–0.05 was numerically obtained for the 5Ti + 3Si samples with 50–60% TMD and well validated by the experimental data.