Abstract
The transverse-rupture strength (σm) of TiC-20%Mo2C-20%Ni(Co) and TiC-20%Mo2C-15%TiN-20%Ni(Co) cermets were studied in the temperature range from 600 to 1000°C; attention was paid to the fracture source. The σm of WC-8%Co alloy having the same volume fraction of binder phase was also studied for comparison.
The results obtained were as follows: the Co-bonded cermets generally showed higher σm than Ni-bonded cermets above about 600°C, and the TiN-free cermets showed higher σm than TiN-bearing cermets above 800-900°C. The strength decrease of cermets with rising temperature was gradual up to 600-800°C. but became sharp above 800-900°C. The latter temperature range of 800-900°C was higher than that of WC-Co alloy, resulting in the higher σm of cermets than WC-Co alloy above about 900°C. These results were discussed in close relation to the fracture source which varied in type and dimension with variation of test temperatures.
