LI Zongjia (1995-), male, Master candidate. E-mai: zongjial@126.com
B4C-TiB2 multi-phase ceramics were prepared in a pressureless vacuum sintering-furnace at different temperatures with TiB2 added into B4C matrix as a second phase substance, and C and Si as sintering aids. The density, hardness, bending strength and fracture toughness of the samples were determined. The influences of composition ratio of B4C-TiB2 and sintering temperature on the microstructure and mechanical properties of the multiphase ceramics were investigated by X-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy. The toughening mechanism of ceramics was discussed. The results show that the optimum density and comprehensive mechanical properties of the multiphase ceramics (i.e., the relative density of 94.59%, the Rockwell hardness of 87.62, the bending strength of 182 MPa, and the fracture toughness of 3.97 MPa·m1/2 can be obtained at a sintering temperature of 2 200 ℃ and TiB2 content of 30%. The TiB2 particles can effectively nail the grain boundary, inhibit the growth of B4C grains and play a role in fine-grain strengthening. The TiB2 and laminated graphite phase hinder the crack growth, thus improving the fracture toughness.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |