Insight into the interface properties of γ-TiAl/α₂-Ti₃Al with La doping obtained by first-principles calculations

Area of Science:

• Materials Science
• Computational Materials Science
• Alloy Design

Background:

• The interface strength between γ-TiAl and α2-Ti3Al phases is critical for the room temperature ductility of TiAl alloys.
• Experimental elucidation of γ-TiAl/α2-Ti3Al interface bonding mechanisms is challenging.

Purpose of the Study:

• To investigate the effects of Lanthanum (La) doping on the properties of the γ-TiAl/α2-Ti3Al interface.
• To understand the bonding mechanisms and stability of the interface with and without La doping.

Main Methods:

• First-principles calculations were employed to simulate and analyze the γ-TiAl/α2-Ti3Al interface.
• Calculations included energy stability, electronic structure, interface binding and energies, tensile tests, and potential energy surface analysis.
• A model of the γ-TiAl/α2-Ti3Al interface was constructed and La atom substitution was simulated.

Main Results:

• La doping at the Doped 5 site minimizes the interface model energy, reducing interface binding and interface energies.
• La doping introduces La-Al bonds, complementing the existing Ti-Ti and Ti-Al bonds.
• Tensile stress, maximum potential energy, and energy barriers for heterogeneous sliding are significantly reduced by La doping, indicating enhanced ductility.

Conclusions:

• Lanthanum doping effectively enhances the ductility of the γ-TiAl/α2-Ti3Al interface.
• The study provides a computational basis for designing improved TiAl alloys through targeted doping.
• Understanding interface properties through first-principles calculations is crucial for advanced materials development.