抄録
In the previous study of the B4C/(W, Mo)B2 hard material, the needle shaped crystals of (W, Mo)B2 were found to be formed by reaction between boron of B4C and tungsten or molybdenum. The needle shaped crystals had effect to improve the bending strength and the fracture toughness. However, the carbon particles appeared on the microstructure after sintering, which were supposed to decrease the strength and the toughness. In this study, boron powder was added on the B4C/(W, Mo)B2 hard materials with the aim of inhibitting the decomposition from B4C to carbon. And the effect of boron content on mechanical properties of the hard material was investigated.
The results were summarized as follows:
(1) The decomposition from B4C to carbon was inhibitted by adding boron powder. And the Vickers hardness was increased by adding boron powder.
(2) The bending strength and the fracture toughness were degraded by adding boron powder.
