Abstract
In this study, different amounts of fine TiC powders (0, 10, 15 and 20 mass%) were mixed and added to cobalt-based alloy powders. Then, the mixed composite materials (cobalt-based alloy and TiC powders) were vacuum sintered at 1260, 1270, 1280 and 1290°C for 1 h, respectively. The experimental results showed that the highest TRS value of 1485.1 MPa was obtained by the addition of 15 mass% TiC powder and sintering at 1280°C for 1 h; while the highest hardness value of HRA 80.4 was obtained by 20 mass% TiC powder sintered at 1290°C for 1 h. In addition, two types of carbide precipitates appeared in the microstructure. Without added TiC powder of the specimen, fine plate-like precipitates of M6C and M23C6 carbides were obvious on the grain boundary; but when TiC powder was added to the specimens, only M23C6 carbides were observed after sintering treatment. The result also showed that a suitable amount of TiC additive (15 mass%) effectively inhibits carbide precipitation and growth.
