Fabrication of Al2O3-B4C Nanocomposite via Ball Milling, Subsequent Self-Propagation High-Temperature Synthesis, and Final Hot Pressing

In this study, the properties of Al2O3-B4C synthesized nanocomposite components were investigated. The Al2O3-B4C nanocomposite powder was synthesized from aluminum, boron oxide, and graphite powders via mechanical alloying route, followed by self-propagation high-temperature synthesis (SHS). In order to produce bulk parts, the nanocomposite powder was sintered by hot pressing at 1400, 1500, and 1600 °C. Characterization of powder samples and bulk parts was performed using X-ray diffraction and scanning electron microscopy. The results of the X-ray diffraction analysis showed that no phase change occurs in the mechanochemical process, instead, the reduction of particle size and proper mixing of the powders encourages the SHS process and product formation. The best results were obtained to the bulk part that sintered at a temperature of 1500 °C with a hardness of 19.6 GPa, 99.4 % relative density, and 6.7 MPa.m1/2 toughness. Also, as the sintering temperature rises to 1600 °C and the density increases, the hardness of the part decreases due to grain growth.