Site Occupancy of the B2 Phase in Ti-25Al-zMo Alloys

The structure of the B2 phase has been investigated in Ti-25Al-30Mo, Ti-25Al-35Mo and Ti-25Al-40Mo alloys using Rietveld refinement of X-ray diffraction data in homogenized condition. Different initial structure models have been used for the refinement based on the analyzed alloy chemistry. Site occupancy models for the general alloy compositions (xTi-yAl-zMo) wherein the Ti (x) is less than 50 atom % have been proposed. The site occupancy of the B2 phase has been calculated and compared with those of earlier experimental and theoretical investigations. The lattice parameter of the B2 phase decreases with increase in Mo content at constant Al.