Full
CHEN Hao (1995-), male, Master candidate. E-mail: 1192343680@qq.com
Outline
Transition metal carbide ceramics are typical representatives of ultra-high temperature ceramics with extremely high melting point and hardness. However, the toughness and wear resistance need to be improved. Based on the high-entropy theory, a multi-carbides solid solution, i.e., high-entropy carbides, has a higher melting point, a good toughness and superior friction/wear characteristics. In this paper, (Ti1/6V1/6Nb1/6Ta1/6Mo1/3)C high-entropy ceramics were prepared via spark plasma sintering (SPS) at 1 600-2 100 ℃, and the densification behavior, phase composition, microstructure, mechanical properties and wear resistance were investigated. The results show that (Ti1/6V1/6Nb1/6Ta1/6Mo1/3)C high-entropy ceramics with a single-phase face-centered cubic structure can be obtained by sintering at 1 700 ℃. The relative density of the high-entropy ceramics is greater than 98% at ≥1 900 ℃. The grain size increases and the elemental distribution becomes uniform as the sintering temperature increases from 1 700 ℃ to 2 100 ℃. The grain boundary sliding and oxide impurities (TiO2) aggregation occur at grain boundaries. The dislocations appear in grains. The optimal mechanical properties of the high-entropy ceramics prepared by sintering at 2 100 ℃ can be obtained, i.e., the Vickers hardness of 20 GPa, elastic modulus of 431 GPa and fracture toughness of 4.46 MPa·m1/2, respectively, and the average specific wear rate is 5×10-7 mm3/(N·m), showing a superior wear resistance.
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| 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 |
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