The Effect of Cr Additive on the Mechanical Properties of Ti-Al Intermetallics by First-Principles Calculations

The structure, elastic properties and electronic structure of Ti-Al intermetallics including Ti3Al (space group P63/mmc), TiAl (space group I4/mmm) and TiAl3 (space group P4/mmm) are systematically studied by first-principles calculations. The results show that Ti-Al intermetallics can exist stably whether Cr replaces Ti or Al. The ductility of the alloy cannot be improved when Ti is replaced in Cr-doped TiAl and TiAl3. However, when it replaces Al, the alloy has better ductility. In Ti3Al, the ductility can be improved regardless of whether Cr replaces Ti or Al, and the effect is better when it replaces Al. The bond in Ti-Al intermetallics is mainly a Ti-Ti metal bond. The metal bond between Ti-Ti is strengthened and a solid metal bond is formed between Cr and Ti, inducing a better ductility of the material, after Cr replaces Al in Ti-Al intermetallics.

Automated summary

The structure, elastic properties and electronic structure of Ti-Al intermetallics were studied by first-principles calculations. Ti-Al intermetallics can stably exist whether Cr replaces Ti or Al. Ductility of the alloy cannot be improved when Ti is replaced in Cr-doped TiAl and TiAl3, but it is improved when it replaces Al. In Ti3Al, ductility can be improved regardless of Cr replaces Ti or Al, with better effect when it replaces Al. The metal bond between Ti-Ti is strengthened and a solid metal bond is formed between Cr and Ti, inducing better ductility after Cr replaces Al in Ti-Al intermetallics.