Synthesis of Ternary Machinable Al2O3/Ti2AlC Composites by High Energy Milling and In Situ Hot-Pressing Method
Al2O3/Ti2AlC composites were synthesized by high energy milling and hot-pressing at 1200°C in a vacuum furnace with a pressure of 4.8×10-2 Pa, using Ti, Al and C powder as raw materials. The effect of sintering temperature on the reactions, phase composition and microstructure of the synthesized products were investigated. The results show that the TiC and TiAl intermetallics composite powders were synthesized during the milling process. After the hot pressing, Ti2AlC phase was formed by the reaction between TiC and TiAl. A small amount of Al2O3 was also produced because of the oxidation of Al in the hot press process, which formed Al2O3/Ti2AlC composite together with the Ti2AlC at 1200°C. The fine grained Al2O3 particles disperse within Ti2AlC uniformly, which play a important role to strengthen Ti2AlC matrix, resulting in the increase of flexural strength and fracture toughness from 250 to 275.4MPa, 9.8 to 10.5MPa•m1/2, respectively.
Hyungsun Kim, JianFeng Yang, Tohru Sekino, Masakazu Anpo and Soo Wohn Lee
F. Wang et al., "Synthesis of Ternary Machinable Al2O3/Ti2AlC Composites by High Energy Milling and In Situ Hot-Pressing Method ", Materials Science Forum, Vol. 658, pp. 169-172, 2010