First-principles study of influence of Ti vacancy and Nb dopant on the bonding of TiAl/TiO2 interface

• Bonding of TiAl/TiO2 interface is associated with O transferring from TiO2 to TiAl.
• Ti vacancy increases bonding interaction between O and Al atoms at TiAl/TiO2 interface.
• Oxygen atoms are shielded by Al atomic layer in Nb-containing TiAl/TiO2 interface.

Influence of defects (Ti vacancy and Nb dopant) on the bonding of TiAl/TiO2 interface was studied via first-principles calculations. It was shown that the bonding strength and the stability of TiAl/TiO2 interface were weakened by the presence of Ti vacancy and dopant Nb. The defects could also change the relative stability of the interface with different couplings between the two compounds. Electronic structure of the interface was analyzed and the influence mechanisms of defects on the bonding of interface were presented.

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