关键词: 陶瓷基复合材料;SHS离心熔铸法;成分净化;微纳米晶补强增韧

Abstract: Based on principle of centrifugal thermal explosion reaction , refractory liquid phase separation and rapid solidification , the micro/nanograined TiB2 reinforced ( Ti,W) C-TiC composite ceramics were successfully prepared by using the reaction systems of ( WO3 +Al+C) and ( B4C+Ti) through the self propagating centrifugal casting technology .The results of experiments after adjusting powder ball -milling, filling mode showed that the Stokes floating process of Al2O3 droplets was greatly promoted due to the decrease of the dynamic viscosity of W-Ti-C liquid phase and the decrease of the migration distance of Al2O3 droplets.As a result, the content and size of Al2O3 inclusions were both reduced greatly in ceramic matrix.Furthermore, because of the synergistic effect of the strong self toughening mechanism induced by TiB2 micro nano lamellae and residual stress toughening effect produced by Al2O3 micro nanocrystals , the bending strength , fracture toughness and Vickers hardness of TiB2-( Ti,W) C-TiC ceramics were (952+25) MPa, (12.6+2.5) MPa/m1/2 and (28.6+1.2) GPa respectively.

Key words: composite ceramics;SHS centrifugal casting;constitutional purification;reinforcement-induced toughening by micro/nanograin