Microstructural evolution and mechanical performance of TiO2 nanoparticle-reinforced Fe2O3–Al reactive composites en en In this study, Fe2O3-Al reactive composite samples containing different concentrations of TiO2 nanoparticles (0.1, 0.2, 0.3, 0.4, and 0.5 wt%) were prepared through ultrasonic mixing followed by thermite combustion in sand molds. Before nanoparticle incorporation, the optimum Fe2O3:Al ratio was determined as 3:1, which produced the highest iron yield (116.2 g) with a reaction time of 26.43 s, falling within the industrially desirable range of 23–28 s. X-ray diffraction (XRD) analysis revealed that the base sample primarily consisted of α-Fe and α-Al2O3 phases, while TiO2-containing samples exhibited additional peaks associated with FeTi and Fe2Ti intermetallic compounds. Field-emission scanning electron microscopy (FESEM) coupled with energy-dispersive spectroscopy (EDS) confirmed a uniform nanoparticle distribution up to 0.4 wt%, whereas noticeable agglomeration was observed at 0.5 wt%. Mechanical characterization demonstrated that the sample containing 0.4 wt% TiO2 exhibited the highest density (7.81 g/cm3, corresponding to a 21.7% increase), hardness (293 HV, 36.3% increase), tensile strength (665 MPa, 35.2% increase), and compressive strength (732 MPa, 18.6% increase). Furthermore, the maximum impact energy (265 J, representing a 61.6% increase) and the highest wear resistance (30% reduction in wear depth) were achieved at the same nanoparticle content. The observed improvements are attributed to combined strengthening mechanisms including grain refinement, Orowan strengthening, crack deflection, and thermal mismatch effects. 161 171 Mostafa Pasban Faculty of Materials and Manufacturing Processes Malek Ashtar University of Technology, Tehran Iran mostafapaseban588@gmail.com Ali Alizadeh Faculty of Materials and Manufacturing Processes Malek Ashtar University of Technology, Tehran Iran Hamid Reza Baharvandi Faculty of Materials and Manufacturing Processes Malek Ashtar University of Technology, Tehran Iran Thermite welding TiO2 nanoparticles Reactive composites FeTi intermetallic compounds Mechanical properties Grain refinement Vol 6 No 3 Paper 1.pdf [1] M.E. Molefe, J.-R. Tapamo, Classification of thermite welding defects using local binary patterns and k-nearest neighbors, Proceedings of the 2021 Conference on Information Communications Technology and Society (ICTAS), IEEE. 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