Abstract
It had been confirmed in the previous work that 70%TiC-15%TiN-7%Mo2C-8%Cr3C2 ceramic composite showed distinguished sinterability similar to liquid phase sintering alloys. That is to say, the complete dense bodies of the composite can obtain by means of sintering at 1623K. Present study was undertaken to reveal the effect of microstructure on properties of the dense ceramic composite in relation to sintering temperature up to 1873K.
The ceramic composites were strengthened, toughened and hardened with accompanied grain growth according to rise of sintering temperature. Bending strength, fracture toughness and Vickers hardness reached the values of about 780 MPa, 4.65 MPa·m1/2 and 24.0 GPa respectively in the specimen sintered at 1823K. The value of strength corresponds to rise of about 300 MPa compared with that of TiC-Cr3C2 system.
It was confirmed in fracture test that the composites have the characteristics of easy branching property of cracks and of slow velocity in crack propagation, which resulted remaining of many branched cracks in the specimens after fracture.
Morphology of cracks in fractured specimens elucidated multi-toughening phenomena in the ceramic composite, comprising branching and deflection of cracks and micro-cracking. And, the rise of strength was presumed due to R-curve behaviour.
