Synthesis of Ti2AlN Cermet Strengthened by A12O3

摘要

Bulk intermetallic-ceramic composites in Ti-Al-N system were fabricated by reactive hot pressing of TiAl3+TiN+TiO2 powders at 1380°C under l0MPa pressure. The phase chemistry and microstructure were characterized by X-ray diffraction and scanning electron microscopy. The mixture with mass ratio of Al3Ti: TiN: TiO2 equal to 2. 07: 1. 68: 1 allows the attainment of an interconnected matrix of Ti2AlN, with 25vol. % A12O3 formed simultaneously. The Vickers hardness and compression strength were measured at room temperature. The hardness of the composite is 9. 7 GPa which is more than twice that of pure Ti2 A1N (3. 5 GPa). The compression strength is 1. 8 GPa, which falls between those of pure Ti2AlN and A12O3. It is concluded that with the homogeneous dispersion of the A12O3 in the matrix, a high hardness of the composite can be achieved.