Structure and stability of the B2 phase in Ti–25Al–25Zr alloy

This paper reports the formation of an ordered B2 phase in the alloy Ti–25Al–25Zr. The structure of the B2 phase has been confirmed by X-ray diffraction and transmission electron microscopic techniques. The B2 phase transforms to two phases (Ti2AlZr and Al3Zr5) and an orthorhombic phase during aging and mechanical polishing, respectively. The instability of B2 phase has been attributed to higher heat of formation of the B2 phase than that of Ti2AlZr (D019) structure.