A First Principles Analysis Of Oxidation In Titanium Alloys With Aluminum And Vanadium

We carry out first principles computations to understand mechanisms of oxygen accommodation on titanium surfaces doped with aluminum and vanadium. Our findings provide explanation in an atomistic level on why titanium alloys such as Ti-6Al-4 V (6 wt. % Al, 4 wt. % V, balance Ti) have a better oxidation resistance than commercially pure titanium. We determine the ground state positions, the related formation (adsorption) energies of oxygen atoms, their migration pathways into the bulk. We also explore the correlation between the concentration-dependent configurational stability of the alloyed surface with the oxygen migration energy. Our results show that oxygen atoms are concentrated on the surface and occupy face centered cubic hollow sites. A relatively high energy barrier for oxygen migration into the titanium lattice is found, indicating that such dopants provide a passivating effect in oxidizing environments