Microstructure Characterization and Thermal Stability of TNM Alloy Fabricated by Powder Hot Isostatic Pressing
A TNM alloy ingot was fabricated with powder hot isostatic pressing (P-HIP) and short-time exposure treatment conducted at 750–1050 °C for 2–5 h. The tensile mechanical properties were investigated at room temperature and 800 °C. The results revealed that a fully lamellar microstructure of P-HIPed T...
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| Autores principales: | , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/da8cfa3dc04c4b6497705ef261119228 |
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| Sumario: | A TNM alloy ingot was fabricated with powder hot isostatic pressing (P-HIP) and short-time exposure treatment conducted at 750–1050 °C for 2–5 h. The tensile mechanical properties were investigated at room temperature and 800 °C. The results revealed that a fully lamellar microstructure of P-HIPed TNM alloy with only 0.3 vol.% β<sub>0</sub> phase could be obtained by hot isostatic pressing at 1260 °C, under the pressure of 170 MPa, held for 4 h. When the exposure temperature was below 850 °C, the α<sub>2</sub> lamellae were transformed into nano-scaled (α<sub>2</sub> + γ) lamellae (i.e., the α<sub>2</sub>→α<sub>2</sub> + γ transformation). With increases in the exposure temperature, the β<sub>0</sub> phase began to precipitate within the α<sub>2</sub> lamellae (α<sub>2</sub>→β<sub>0</sub> transformation) at 950 °C. The α<sub>2</sub>→γ and the α<sub>2</sub>→β<sub>0</sub> transformation both happened at 950–1050 °C, and the higher exposure temperature accelerated the diffusion of Mo and facilitated the α<sub>2</sub>→β<sub>0</sub> transformation. The yield strength and elongation at RT and 800 °C were both improved after short-time high-temperature exposure treatment. The uniform distribution and nano-scaled interfacial β<sub>0</sub> phase provided precipitation strengthening and were not harmful to the elongation. |
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