FINE-GRAINED TiC(Ti,W)C_(1-x) MATRIX CERAMICS PREPARED BY COMBUSTION SYNTHESIS UNDER HIGH GRAVITY

By using self-pressing assisted combustion synthesis under high gravity,fine-grained TiC-(Ti,W)C1-x matrix ceramics were achieved through rapid solidification.XRD,FESEM and EDS results show that TiC-(Ti,W)C1-x matrix ceramics are mainly composed of spherical fine TiC grains,and in the matrix there distribute a few TiB2,(Cr,W,Ti)3B2 and residual Al2O3 inclusions.because of the introduction of high gravity,the molten products from combustion reaction are layered.As a result of high concentration of Ti and C in Ti-W-Cr-C-B liquid at the bottom of the melt,TiC solids nucleate and grow rapidly as the primary phase,leading to the formation of e(Ti,W)C1-x solids and the development of TiC-(Ti,W)C1-x matrix microstructures.Mechanical properties show that relative density and Vickers hardness of the ceramics are 99.3% and 22.5±1.5 GPa respectively.