Preparation and Characterization of Ti-12Mo/X Al2O3 Nano-Composites for Aerospace Applications

Abstract

Titanium powder is reinforced with 12 wt. % molybdenum powder, and then the mixed Ti-12%Mo matrix composite powder is reinforced with 5, 10, and 15 wt. % nano Al2O3 by the mechanical milling for 24 hr. The mixed nano-composite powders were cold compacted under 600MPa, then sintered at 1450°C for 90 min. The microstructure and chemical composition of the Ti-12Mo/Al2O3 powders, as well as the fabricated composites, were investigated by both SEM and X-ray diffraction. It has been observed form the SEM studies of the sintered samples that the Al2O3 and Mo particles were homogeneously distributed all over the Ti matrix. All the composites were evaluated by measuring their density, hardness, and wear resistance. The results revealed that the addition of 12 wt. % Mo to pure titanium improves its density due to its high density over than that of the Ti and the good adhesion between them, while the addition of Al2O3 decreases the density of the Ti-12Mo nano-composite. Not only the density of the Ti was improved by the addition of Mo, but also the hardness and wear resistance were also increased. Regardless of the decreasing in the density of Ti-12Mo nano-composite by increasing the Al2O3 wt. %, the hardness and wear resistance were improved up to 5 wt. % Al2O3.