Microstructure and properties of Ti5Si3-based porous intermetallic compounds fabricated via combustion synthesis

Abstract

Porous titanium silicides (Ti5Si3-based) were produced by combustion synthesis process from reaction mixtures of titanium to silicon in varying molar ratios. The effects of combustion characteristics of the reaction mixtures on the phase formation, microstructure, porosity, pore size and compressive strength of porous titanium silicide intermetallic compounds were investigated. The results showed that the flame-front propagation velocity and temperature of the combustion reaction were the maximum for the reaction mixture containing Ti and Si in the ratio of 5–3 (Ti5Si3), 32.7mm/s and 2205K, respectively. X-ray diffraction analysis confirmed that the dominant phase formed was Ti5Si3 in all combustion synthesized porous intermetallic compounds. Ti5Si3-based intermetallic compounds were highly porous. The porosity and pore size of these intermetallics were dependent on the initial composition of the reaction mixture. The total and open porosities of Ti5Si3-based intermetallics varied from 33% to 61% and 17% to 55%, respectively. The porous titanium silicide intermetallic materials displayed high mechanical strength, in the range of 6–35MPa, duly required for their use as filters.