Determination of the composition of titanium-based alloys by neutron diffraction

Titanium-based solid solution alloys with the general composition Ti_xMo_{1 – x}C_yN_{1 – y} and a face-centered cubic (FCC) NaCl-type structure have attracted considerable attention due to their remarkable hardness, thermal and oxidation resistance, and chemical stability, making them indispensable in modern engineering, coating, and biomedical applications. The mechanical and physical behavior of these alloys is governed by their atomic-scale chemical composition, particularly by the ratio of transition metal and interstitial elements. However, despite extensive experimental and computational research, the correlation between elemental distribution and the resulting mechanical characteristics remains insufficiently understood. This limitation is largely associated with the drawbacks of conventional chemical analysis techniques, which are often destructive, lack precision at the atomic scale, and preclude repeated investigations. The present study aims to assess the potential of neutron diffraction as a precise and non-destructive method for determining the atomic composition and crystal structure of multicomponent Ti_xMo_{1 – x}C_yN_{1 – y} solid solutions. Experimental investigations confirmed that all synthesized alloys possess a NaCl-type crystal structure corresponding to the same space group as titanium carbide and nitride. Analysis of neutron diffraction data performed using the FullProf software demonstrated that titanium and molybdenum atoms occupy equivalent 4b lattice sites, while carbon and nitrogen atoms statistically substitute each other in octahedral 4a positions. The refined Rietveld parameters — including the reliability factors and lattice constant — exhibited excellent agreement between the calculated and experimental values, with deviations not exceeding 3%. These findings validate neutron diffraction as a powerful technique for accurate quantitative structural characterization of multicomponent carbides and carbonitrides. The proposed approach can be extended to other NaCl-type alloys containing heavy and light elements, offering a reliable pathway for the non-destructive evaluation and design of advanced heat- and wear-resistant materials.

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