Study of Oxidation Resistance on Ti-Al Alloys

Results show that a decrease in Al content resulted in an increase in the amount of alpha2-Ti3Al phase, which led to an increase in the strength of the alloys but gave detrimental effect to the specific weight. In contrast, the higher Cr addition shows an increase in both strength and specific weight of the alloys. In addition, suitable amount of Cr addition (<15 at.%) can enhance high-temperature oxidation resistance of the alloys due to the existence of Laves and gamma phases as in the Ti-42Al-27Cr alloy. On the contrary, the presence of beta phase in Ti-45Al-10Cr alloy provides the lowest oxidation resistance. It is clear that the heat treatment process in this study gives some improvements in hardness and density of the alloys. On the other hand, the heat-treatment only improves high-temperature oxidation resistance in Ti-Al binary system alloys and not in the ternary system of the alloys.