In situ fabrication of Al-Al2O3-TiB2 hybrid nanocomposite; evaluating the effect of TiO2 and B2O3 mechanical milling time on properties of composite created through vortex casting

In this study, the fabrication of Al-Al2O3-TiB2 hybrid composite using TiO2, B2O3, and Al5083 powders through aluminothermy method has been studied. TiO2, B2O3, and Al5083 powders were attrition milled (20:1 bullet to powder ratio, under argon atmosphere, the speed of 650 rpm for 2, 4, 6 and 20 h). After the completion of the milling process, the milled powder was added to the aluminum molten at 900 °C and finally, the Al5083-Al2O3-TiB2 composite was produced in situ. After the hot extrusion process, specimens were characterized by SEM and XRD analyses and the strength of the composite was investigated. The results of the microstructure analysis and the strength of the specimens indicate the efficiency of low milling times and the absence of TiB2 in milling. The observations from microstructure show presence of TiB2 ceramic particles less than 300 nm in size. The strength tests done on 2, 4, 6 and 20-h specimens represent values of 294, 336, 295 and 276 MPa, respectively.