Nanocrystalline cubic Ti0.9Si0.1B phase has been prepared by mechanical alloying the stoichiometric mixture of Ti, Si and boron powders at room temperature in a planetary ball mill under argon atmosphere. Microstructure characterizations of unmilled and all ball-milled powders in terms of lattice imperfection are made by analyzing respective X-ray diffraction data employing the Rietveld's powder structure refinement method. It reveals that after 1 h of milling, alpha-Ti (hcp) phase is partially transformed to metastable beta-Ti (bcc) phase and the initiation of Ti0.9Si0.1B phase takes place. Contamination free stoichiometric nanocrystalline cubic Ti0.9Si0.1B phase is synthesized within 3 h of milling with similar to 3 nm particle size. Microstructure characterization of 17 h milled sample by high resolution transmission electron microscopy (HRTEM) reveals that the average size of almost monodispersed spherical particles is similar to 5 nm which corroborates the finding of the Rietveld analysis. (C) 2014 Elsevier B.V. All rights reserved.