Energetics of Ti and Zr transition metals in D03-Fe3Al and its Σ5 (310) [001] grain boundary

The substitution of Ti and Zr transition metals in the bulk volume as well as at the interface of a ∑5 (310)[001] grain boundary of an ordered (D03-Fe3Al) intermetallic were studied by means of ab-initio calculations. The results show that both Ti and Zr prefer to segregate at the grain boundary for Fe types of site. It is demonstrated that the major difference between these two types of atoms is the solubility of Ti in the bulk while Zr substitution in the bulk is not energetically favoured. The preferred site for Ti substitution is confirmed to be FeI. Emphasis is also given on the importance of using relaxation when determining energy formation calculation for site preference configurations.

► The formation energies of Ti and Zr are calculated in the bulk and at ∑5 grain boundary of D03-Fe3Al.
► Relaxation is important to determine accurate formation energies and stability of point defects.
► Zr has very limited solubility in bulk Fe3Al. Ti atoms are soluble in the bulk and prefer to reside in the FeI site.