Effects of Raw Material Molar Ratio and Addition of Mg on Titanium Aluminide–Alumina Composite Formation Mechanism

In this study, the effects of molar ratio of the raw materials (TiO 2 and Al) and the addition of Mg on the titanium aluminide–alumina composite formation mechanism were investigated. To do this, in the first step, three molar ratios of 1.5 : 6.5, 1.5 : 3.5, and 3 : 5 of TiO 2 : Al, with no presence of Mg and, in the second step, the same molar ratios with 2 wt.% Mg were used. Differential thermal analysis was applied to determine the critical temperatures of each ratio. Based on DTA results, the heat treatment was performed. It is found that with increasing the aluminum content, the reactions accelerate due to merge of the sub-reactions, and subsequently this causes the transient phase number to decrease. In the second step of the experiments, Mg was added to the previously mentioned molar ratios of TiO and Al. Mg reduced the reaction temperatures and accelerated the reaction processes as a result of low melting point eutectic formation.