Influence of aluminum content in γ-TiAl with L1₀ structure during ordering processes

Based on EAM (embedded atom method) interatomic potential, the effect of aluminum content on the type of order-disorder transformation (ODT) and the structure properties (lattice constants, volume, c/a ratio and configuration energy) during ordering processes was investigated for γ-TiAl based alloys. Results show that for the alloys with lower than 50% Al (all composition is in atom number fraction), the ODT is the first order transition, and the second order transition for the alloys with equal or higher than 50% Al. The increase of aluminum content results in the critical temperature increasing. The aluminum content has very little effect on the lattice constants, the volume and the c/a ratio, but has significant effect on the configuration energy. A metastable disordered state was found for the alloys with less than 50% Al.