OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 1 2025 Dwivedi et al. [15] summarized that the addition of TiO2 to AA2014 and AA2024 aluminum alloys improves its wear resistance. Kumar et al. [49] also confirmed that the wear resistance and microhardness of the aluminummatrix increase with increasing TiO2 content. Ahamad et al. [50] explained that the wear resistance of a hybrid composite (Al-Al2O3-TiO2) increases with an increasing of TiO2 content, which is related to its lubricating properties. Conclusion 1. The wall thickness of the casting mold is one of the key parameters determining the solidification rate of the casting. The grains get finer as the cooling rate rises in tandem with the thickness of the mold wall. 2. The microstructure varies with cooling rate during solidification. Slow solidification, characteristic of molds with small wall thicknesses, leads to the formation of a coarse-grained structure. At the same time, a high solidification rate ensures the obtaining of a fine-grained structure with improved mechanical properties. 3. Increasing the mold wall thickness enhances the microhardness of the casting surface by promoting rapid cooling at the casting surface close to the wall. 4. Stir casting was successfully used to fabricate Al- 7Si matrix composites reinforced with varying wt.% of TiO2 nanoparticles. Optimal parameters are found to be as follows: 750 °C pouring temperature, 550 rpm stirring speed, and 5 minute stirring time. 5. Increasing the wt.% of TiO2 nanoparticles affects the density and porosity of the composites. The theoretical density of the composites increases with the addition of TiO2 nanoparticles. However, the experimental density values are lower than the theoretical values due to the presence of porosity within the composites. 6. The hardness and wear resistance of the composites are significantly improved by increasing the wt.% of TiO2 nanoparticles. References 1. Liu J., Chen X., Wang W., Zhao Y., He N. Effect of TiB2 nanoparticle content on the microstructure and mechanical properties of TiB2/Mg-4Al-1.5Si composites. Materials, 2023, vol. 16, p. 2852. DOI: 10.3390/ ma16072852. 2. Nassar A.E., Nassar E.E. Properties of aluminum matrix nano composites prepared by powder metallurgy processing. Journal of King Saud University – Engineering Sciences, 2017, vol. 29 (3), pp. 295–299. DOI: 10.1016/j. jksues.2015.11.001. 3. Tahamtan S., Halvaee A., Emamy M., Zabihi M.S. Fabrication of Al/A206–Al2O3 nano/micro composite by combining ball milling and stir casting technology. Materials and Design, 2013, vol. 49, pp. 347–359. 4. Soltani M.A., Jamaati R., Toroghinejad M.R. The influence of TiO2 nano particles on bond strength of cold roll bonded aluminum strips. Materials Science and Engineering: A, 2012, vol. 550, pp. 367–374. 5. Saber D., Taha I.B.M., Abd El-Aziz Kh. Wear behavior prediction for Cu/TiO2 nanocomposite based on optimal regression methods. Materials Research, 2023, vol. 26, p. e20220263. 6. Jin Z., Jia L., Wang W., Liu Y., Qi Y., Zhang H. Effect of cooling rate on microstructure and properties of SiCP/ A359 composites. Materials & Design, 2023, vol. 234, p. 112297. 7. Megahed M., Saber D., Agwа M.A. Modeling of wear behavior of Al-Si/Al2O3 metal matrix composites. Physics of Metals and Metallography, 2019, vol. 120 (10), pp. 981–988. 8. Shet V.S., Mahadev U.M. Investigation on tribological behavior of metal matrix composites (Al6063-TiO2). International Journal of Recent Engineering Research and Development (IJRERD), 2017, vol. 2 (8), pp. 117–148. 9. Saber D., Abd El-Aziz Kh., Abdel-Karim R., Kandel A.A. Corrosive wear of alumina particles reinforced Al– Si alloy composites. Physics of Metals and Metallography, 2020, vol. 121 (2), pp. 197–203. 10. Abd El-Aziz Kh., Ahmed E.M., Alghtani A.H., Felemban B.F., Ali H.T., Megahed M., Saber D. Development of Al–Mg–Si alloy performance by addition of grain refiner Al–5Ti–1B alloy. Science Progress, 2021, vol. 104 (2). DOI: 10.1177/00368504211029469. 11. Mahan H.M., Konovalov S.V., Osintsev K., Panchenko I. The influence of TiO2 nanoparticles on the mechanical properties and microstructure of AA2024 aluminium alloy. Materials and Technology, 2023, vol. 57 (4), pp. 379–384.
RkJQdWJsaXNoZXIy MTk0ODM1