Description
Over a number of decades, titanium aluminide intermetallics have been of high scientific and industrial interest due to their good mechanical properties and oxidation resistance. Despite Ti3Al and TiAl receiving the vast majority of this interest, less work has been conducted on the Al_Ti intermetallics. In the present work, titanium aluminide (Al_Ti) has been reactively processed from elemental powder using a combined mechanical and electrical activation approach. The effect of mechanical activation and electric current intensity on the ignition and phase development is discussed. An increase in current intensity was found to result in an increase in product homogeneity and product porosity. A secondary reaction and sustained glow was found to occur only at the higher current intensity used, which in turn increased the product homogeneity. Ignition was not possible when powders were milled for short durations, while prolonged milling resulted in mechanical activation that promoted a self-propagating type ignition event. The time to reaction (where the whole compact was engulfed with the reaction wave) was found to decrease with an increase in current intensity. The compacts subjected to the highest current intensity of 1000A, possessed the lowest hardness due to the excessive porosity generated. Such materials maybe suitable for high-temperature oxidation resistant filter applications
