“…Some experimental studies on phase relationship for the alloys showed that the continuous ordering of Nb atoms in the Ti sublattice of -TiAl appears with increasing Nb content, resulting in the Nb atoms to occupy specific Ti sublattices to finally form a new ternary ordered phase named [3,4,5,6,7,8,9]. The phase has been confirmed as a stable phase [4,5,6,7,8,9]. It has the determined chemical formula of TiNbAl and the tetragonal structure with space group , lattice constant a in the range of 5.58–5.84 Å and lattice constant c in the range of 8.15–8.45 Å [4,5].…”