Effects of mechanical alloying (MA) and titanium (Ti) content on the effective lattice parameter, crystallite size and lattice strain of the W-xTi (x=0.5, 1.0, 4.0 and 10.0 wt% Ti) alloys were investigated. Using TOPAS 5 (Bruker AXS) software and Vegard's law, effective lattice parameters, a(eff) were determined from the X-ray diffraction (XRD) peak shift values at different MA durations and Ti contents. Lattice strain and crystallite sizes at varying MA durations and Ti contents were calculated by the Williamson-Hall method and Lorentzian rule using the TOPAS 5 (Bruker AXS) software. As expected, with increasing MA durations and Ti contents, effective lattice parameter and strain values increased and crystallite sizes decreased. Deviations of measured effective lattice parameter values from Vegard's law were analyzed. Negative deviations from the Vegard's law exist for the W-xTi (x=0.5, 1.0, 4.0 and 10.0 wt% Ti) alloys MA'd for 10 h and a maximum solubility of 11 at% Ti was estimated for the W-10 wt%Ti alloy MA'd for 10 h. The smallest crystallite size of 2.21 nm and the maximum strain of 4.57% were calculated for the W-4 wt%Ti alloy MA'd for 20 h. (C) 2016 Elsevier B.V. All rights reserved.