Computational Assessment of TiB Formation During Vacuum Sintering of Ti–TiB2 Composites: Reaction Kinetics, Phase Composition, and Sensitivity Analysis

The formation of TiB reinforcement during the sintering of Ti–TiB2 powder mixtures depends on reaction kinetics and processing conditions, which influence the phase composition available for subsequent thermomechanical treatment. This study presents a reproducible computational assessment of TiB formation in a nominal Ti–5 wt.% TiB2 composite subjected to vacuum sintering for 4 h at 1050, 1150, 1200, 1250, and 1350 °C. A published two-pathway Avrami kinetic model was implemented and evaluated against 25 reported conversion observations, yielding a root-mean-square error of 0.0419 and a mean absolute error of 0.0312 in the conversion fraction. Under the original kinetic parameters, the model predicts nearly complete TiB2 conversion at all five temperatures after 4 h. Stoichiometric mass balance indicates a theoretical maximum of approximately 8.44 wt.% TiB and 91.56 wt.% residual Ti matrix. A kinetic sensitivity analysis was conducted to examine the influence of reduced effective reaction rates on the predicted phase fractions. The results demonstrate that the nominal sintering conditions alone are insufficient to establish a unique phase composition when the kinetic parameters are transferred to powders with different particle sizes and compaction histories. The proposed computational framework provides a transparent basis for evaluating reaction-related processing uncertainties and identifying conditions requiring experimental verification before hot rolling. The analysis does not independently establish densification, reinforcement morphology, or mechanical properties, and its applicability to the investigated powder system remains subject to material-specific validation.