Structure and mechanical properties of γ-Ti-48Al-2Cr-2Nb alloy processed by additive manufacturing

As promising high-temperature materials, γ-TiAl alloys encounter application challenges due to their limited room-temperature ductility, insufficient high-temperature strength, and poor oxidation resistance. TiAl-4822 (Ti-48Al-2Cr-2Nb at. %) addresses these limitations via controlling Cr and Nb alloying additions to optimize the mechanical and microstructural characteristics. This study investigated the optimal doping positions of Cr and Nb in the γ phase of TiAl-4822 alloy and their impacts on the microstructure and mechanical performance by integrating Density Functional Theory (DFT), XRD (X-ray Diffraction) Rietveld refinement, and additive manufacturing technology. The results suggest that the Nb and Cr atoms preferentially substitute Ti sites, uniformly distributed in the γ phase of the second deposited layer, forming a (Ti_0.92Nb_0.04Cr_0.04)Al structure. This lattice configuration exhibits the optimal structural and thermodynamic stability. The mechanical tests demonstrated significant enhancements in Young’s modulus across all directions compared to binary γ-TiAl, indicating improved mechanical performance. This work provides theoretical support for the study on microstructure and mechanical properties of TiAl-4822 by revealing the most stable configurations of Cr and Nb and their effects on the mechanical properties of TiAl alloy.

© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature, 2026