To improve the high-temperature performance of GH5188 cobalt-based superalloy, 10%(volume fraction) TiC particle-reinforced GH5188 composites are fabricated by laser melting deposition (LMD). The microstructure and tensile properties are investigated, and the interfacial forming mechanism and the cause of the high-temperature performance degradation are discussed. The results show that the composite consists of TiC, (W,Ti)C1-x, and the austenitic γ phase. The submicron-thick (W,Ti)C1-x interfacial layer forms between the TiC particles and the matrix. The interfacial layer originates from the partial dissolution of TiC and the diffusion and substitution of W elements during the laser melting deposition process. At room temperature, the ultimate tensile strength (UTS) of the composite reaches 1198.9 MPa, which is 24.3% higher than that of the matrix alloy (964.3 MPa). However, at 1000 ℃, the UTS of the composite is 128.7 MPa, which is lower than the 162.5 MPa of the matrix alloy, with a decrease of 20.8%. The degradation in high-temperature strength is mainly due to the consumption of W elements in the matrix by the (W,Ti)C1-x interfacial layer, resulting in decrease in its mass fraction and weakening the solid-solution strengthening and dislocation-pinning effects on the matrix.
| 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 |