Re-Melting Nb–Si-Based Ultrahigh-Temperature Alloys in Ceramic Mold Shells
Abstract
:1. Introduction
2. Materials and Methods
2.1. Master Alloy Preparation
2.2. Mold Shells Preparation
2.3. Re-Melting Operation
2.4. Inspection of the Samples
3. Results
3.1. Microstructure and Phase Composition of the Master Alloy
3.2. Macroscopic Features of the Samples after Re-Melting
3.3. Microstructure and Composition of the Re-Melted Alloy
3.4. Interfaces between the Alloy and the Ceramic Mold Shells after Re-Melting
4. Discussion
4.1. Formation of a Carbides Layer on the Surface of the Alloy Re-Melted in the Furnace with the Graphite Heating Element
4.2. Formation of the Microstructure of the Alloy Re-Melted in the Furnace with the Graphite Heating Element
4.3. Interactions between the Mold Shells and the Alloy Re-Melted in the Furnace with the Graphite Heating Element
5. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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Zones | Compositions/% | |||||||
---|---|---|---|---|---|---|---|---|
Nb | Ti | Si | Hf | Cr | Al | O | C | |
1 | 28.87 | 11.96 | 9.66 | 1.53 | 2.51 | 1.70 | 14.17 | 29.60 |
Re-normalization | 51.48 | 21.17 | 17.28 | 2.63 | 4.41 | 3.02 | - | - |
2 | 25.10 | 9.65 | 6.55 | 0.78 | 2.06 | 1.51 | 14.38 | 39.96 |
Re-normalization | 54.98 | 21.14 | 14.35 | 1.71 | 4.51 | 3.31 | - | - |
3 | 21.84 | 8.99 | 5.25 | 0.29 | 2.34 | 0.91 | 7.13 | 53.25 |
Re-normalization | 55.12 | 22.70 | 13.25 | 0.73 | 5.91 | 2.29 | - | - |
4 | 23.37 | 7.94 | 6.50 | 0.33 | 2.78 | 1.63 | 7.09 | 50.36 |
Re-normalization | 54.92 | 18.66 | 15.28 | 0.78 | 6.53 | 3.83 | - | - |
5 | 22.20 | 9.33 | 4.88 | 0.47 | 2.25 | 1.12 | 8.73 | 51.02 |
Re-normalization | 55.16 | 23.18 | 12.12 | 1.17 | 5.59 | 2.78 | - | - |
6 | 25.27 | 8.24 | 6.95 | 0.39 | 2.71 | 1.47 | 7.47 | 47.51 |
Re-normalization | 56.12 | 18.30 | 15.43 | 0.87 | 6.02 | 3.26 | - | - |
Mold Shells | Furnace Heating Element | Phase Composition | Position | Thickness/μm | Formation Mode |
---|---|---|---|---|---|
Y | Tungsten | HfO2 + Y2O3 | On the interface | 1.5 | Interface reaction |
Z | Tungsten | HfO2 | On the interface | 58.1 | Interface reaction |
Y | Graphite | Y2O3 + Y–Al and Y–Ti composite oxides | In Y mold shell adjacent to interface | - | Infiltration reaction |
Z | Graphite | ZrO2 + Zr–Ti composite oxides | In Z mold shell adjacent to interface | - | Infiltration reaction |
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Wang, Y.; Guo, X. Re-Melting Nb–Si-Based Ultrahigh-Temperature Alloys in Ceramic Mold Shells. Metals 2019, 9, 721. https://doi.org/10.3390/met9070721
Wang Y, Guo X. Re-Melting Nb–Si-Based Ultrahigh-Temperature Alloys in Ceramic Mold Shells. Metals. 2019; 9(7):721. https://doi.org/10.3390/met9070721
Chicago/Turabian StyleWang, Yin, and Xiping Guo. 2019. "Re-Melting Nb–Si-Based Ultrahigh-Temperature Alloys in Ceramic Mold Shells" Metals 9, no. 7: 721. https://doi.org/10.3390/met9070721