A STUDY OF COMBUSTION SYNTHESIS OF TI-AL INTERMETALLIC COMPOUNDS

The mechanisms involved in the combustion synthesis of TI-AI intermeta llics have been studied by quenching partially transformed pellets to suppress the reaction prior to its completion. The reaction steps lead ing to the formation of TiAl3, TiAl or Ti3Al were found to be similar in all three compositions used for the study. In each case the initial product detected by X-ray diffraction was TiAl3, while substantial di ssolution of Ti into molten Al was found. At the same time the molten AI-TI liquid adsorbed oxygen, and on quenching the partially transform ed pellet, a glass was formed from the liquid. If the com bustion synt hesis process was completed, the oxygen-rich liquid decomposed, yieldi ng a mixture of oxides and intermetallic compounds.