Effect of Ti Particle Size on the Reaction Kinetics and Densification of TiAl Intermetallics

The present investigation deals with response of the particle size of titanium on the reactive sintering of Ti–Al intermetallics and subsequently on their reaction kinetics and densification behavior. Titanium powders of the initial average particle size of 44 μm were milled for various durations in a planetary ball mill to produce average particle sizes of 100, 28 and 7 μm. These titanium powders of various particle sizes, i.e. 100, 28, and 7 μm were mixed with titanium powder of average particle size range of 40–44 μm in the ratio of 1:1 corresponding to the Ti–Al intermetallic composition. The reactive sintering temperatures of the mixtures were determined by DTA and the effect of change in Al particle size was determined for the activation energy of the self propagating reaction. The mixtures of Ti and Al blends of various Ti particle size were compacted and subsequently sintered at reaction sintering temperatures for 1 h in argon atmosphere. The porosity levels as well as the microstructure studies were carried out to determine the influence of the particle size of aluminium on the reactive sintering of Ti–Al. The compacts were further characterized by X-ray diffraction to determine the extent of phase formation.