On the Microstructure and Properties of Nb-12Ti-18Si-6Ta-2.5W-1Hf (at.%) Silicide-Based Alloys with Ge and Sn Additions
Abstract
:1. Introduction
2. Alloy Design and Selection
3. Experimental
4. Results
4.1. Alloy JZ1
4.2. Alloy JZ2
4.3. Oxidation
4.3.1. Oxidation at 800 °C
4.3.2. Oxidation at 1200 °C
5. Discussion
5.1. Densities
5.2. Macrosegregation
5.3. Microstructures
5.4. Oxidation
5.4.1. Oxidation at 800 °C
5.4.2. Oxidation at 1200 °C
5.5. Comparisons of Experimental Data with NICE
Creep
6. Summary
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Area Phase | Nb | Ti | Si | Ta | W | Sn | Ge | Hf |
---|---|---|---|---|---|---|---|---|
As-cast | ||||||||
Top | 55.1 ± 0.8 54.0–55.9 | 11.9 ± 0.6 11.3–12.7 | 22.3 ± 1.7 20.4–24.4 | 5.4 ± 0.3 5.2–5.8 | 1.6 ± 0.3 1.4–2.0 | 1.1 ± 0.2 0.9–1.3 | 1.8 ± 0.1 1.7–2.0 | 0.8 ± 0.1 0.7–0.9 |
Bulk | 55.1 ± 0.9 53.5–56.0 | 11.4 ± 0.2 11.1–11.6 | 22.9 ± 1.6 21.2–23.0 | 5.1 ± 0.4 4.6–5.7 | 1.6 ± 0.3 1.3–1.9 | 1.2 ± 0.1 1.1–1.3 | 1.8 ± 0.2 1.6–2.1 | 0.9 ± 0.2 0.8–1.1 |
Bottom | 55.4 ± 2.0 53.5–57.6 | 11.4 ± 0.2 11.3–11.7 | 22.3 ± 2.6 19.0–24.6 | 5.5 0.4 5.1–6.2 | 1.7 0.4 1.3–2.3 | 1.1 ± 0.2 0.9–1.3 | 1.8 0.2 1.6–2.0 | 0.8 0.1 0.6–0.9 |
Nbss | 68.2 0.6 67.1–69.4 | 11.8 1.7 9.4–13.9 | 4.4 0.9 3.6–5.4 | 8.5 0.5 7.7–9.2 | 4.5 0.4 3.8–5.3 | 1.7 0.3 1.2–2.0 | 0.5 0.1 0.3–0.7 | 0.4 0.1 0.2–0.6 |
Ti–rich Nbss | 61.1± 1.6 59.6–64.5 | 22.7 1.8 21.6–24.8 | 4.2 1.1 3.1–5.6 | 5.5 0.7 4.4–6.9 | 1.8 0.4 1.0–2.4 | 3.0 0.2 2.7–3.5 | 0.6 0.1 0.4–0.7 | 1.1 0.2 0.9–1.4 |
Nb5Si3 | 48.4 0.3 47.7–48.6 | 7.8 0.2 7.4–8.0 | 36.3 0.6 35.4–37.2 | 3.9 0.2 3.6–4.2 | 0.3 0.1 0.1–0.5 | 0.5 0.1 0.4–0.7 | 2.3 0.1 2.1–2.6 | 0.5 0.1 0.4–0.6 |
Ti-rich Nb5Si3 | 46.3 0.7 45.1–47.0 | 11.9 0.9 10.9–12.9 | 34.5 0.7 34.0–35.7 | 2.9 0.2 2.5–3.1 | 0.1 | 0.6 0.1 0.5–0.7 | 2.8 0.2 2.6–3.0 | 0.9 0.2 0.7–1.1 |
Nb3Si | 55.9 0.4 55.2–56.1 | 8.0 0.1 7.8–8.1 | 26.20.5 25.7–26.9 | 6.5 0.2 6.2–6.8 | 1.5 0.1 1.3–1.6 | 0 | 1.4 0.1 1.4–1.5 | 0.5 0.1 0.4–0.6 |
Eutectic | 58.8 0.6 58.0–59.8 | 10.8 0.7 9.9–11.9 | 18.2 0.6 16.1–18.1 | 6.2 0.3 6.1–6.8 | 2.8 0.2 2.7–3.2 | 1.3 0.1 1.2–1.6 | 1.2 0.2 0.9–1.5 | 0.7 0.1 0.4–0.8 |
Heat-treated | ||||||||
Large area | 55.0 1.3 53.3–56.9 | 12.0 0.4 11.5–12.8 | 22.4 1.6 20.1–24.5 | 5.2 0.3 4.6–5.5 | 1.6 0.3 1.1–2.1 | 1.2 0.2 1.0–1.5 | 1.8 0.2 1.5–2.1 | 0.8 0.1 0.7–0.9 |
Nbss | 69.3 0.5 68.7–69.8 | 12.3 0.2 12.1–12.6 | 3.8 0.7 3.1–4.7 | 8.0 0.3 7.5–8.3 | 4.0 0.2 3.8–4.3 | 2.3 0.1 2.2–2.4 | 0.3 0.1 0.2–0.3 | 0 |
Nb5Si3 | 48.3 0.4 47.9–48.8 | 7.9 0.2 7.7–8.2 | 35.9 0.4 35.4–36.4 | 4.1 0.1 3.9–4.2 | 0.4 0.1 0.2–0.4 | 0.6 0.1 0.5–0.7 | 2.3 0.2 2.0–2.4 | 0.5 0.1 04–0.5 |
Ti-rich Nb5Si3 | 44.8 0.5 44.0–45.2 | 12.5 0.4 12.1–13.0 | 35.3 0.6 34.3–35.8 | 2.8 0.2 2.4–3.1 | 0 | 0.7 0.1 0.5–0.8 | 2.9 0.3 2.7–3.3 | 1.0 0.2 0.8–1.2 |
Alloy | Density (g/cm3) | % Area Nbss a | ||
---|---|---|---|---|
Top | Bulk | Bottom | ||
JZ1-AC a | 8.240.02 8.2–8.26 | 42.3 0.7 41.3–43 | 46.5 0.8 45.4–47.6 | 46.51.0 45.4–48.2 |
JZ1-HT | - | - | 46.5 1.5 44–48.2 | - |
JZ2-AC a | 8.31 0.02 8.28–8.33 | 32.9 1.1 32.1–34.1 | 34.5 1.0 33.9–35.6 | 21.9 1.1 20.7–22.7 |
JZ2-HT | - | - | 23.52.7 20.4–25.4 | - |
Area Phase | Nb | Ti | Si | Ta | W | Sn | Ge | Hf |
---|---|---|---|---|---|---|---|---|
As-cast | ||||||||
Top | 50.7 0.9 49.0–50.5 | 11.6 0.2 11.4–12.0 | 21.6 1.7 19.2–23.7 | 5.4 0.5 4.8–6.2 | 1.9 0.2 1.7–2.1 | 2.6 0.2 2.3–2.9 | 5.3 0.4 4.8–5.9 | 0.9 0.1 0.8–1.0 |
Bulk | 50.3 0.2 50.2–50.7 | 11.7 0.4 11.3–12.4 | 21.7 1.2 20.0–23.0 | 5.3 0.3 5.0–5.7 | 2.0 0.2 1.8–2.2 | 2.5 0.3 2.1–2.8 | 5.4 0.7 5.0–6.6 | 1.1 0.1 0.9–1.3 |
Bottom | 50.8 0.9 50.1–52.1 | 12.1 0.5 11.4–12.7 | 21.1 1.7 18.8–22.5 | 4.9 0.4 4.5–5.6 | 2.0 0.2 1.9–2.4 | 3.2 0.3 2.9–3.6 | 4.9 0.2 4.7–5.1 | 1.0 0.2 0.8–1.3 |
Nbss | 63.7 0.7 62.9–64.7 | 11.5 1.0 10.6–12.9 | 3.4 0.4 3.1–4.1 | 9.3 0.5 8.7–9.8 | 6.5 0.4 5.9–7.0 | 4.1 0.4 3.9–4.8 | 1.0 0.2 0.8–1.2 | 0.5 0.1 0.3–0.6 |
Ti–rich Nbss | 61.4 0.9 60.3–62.4 | 15.5 1.1 14.7–17.4 | 4.0 0.5 3.5–4.7 | 7.6 0.5 7.0–8.1 | 4.4 0.4 3.7–4.7 | 5.5 0.4 5.1–6.1 | 1.0 0.1 0.8–1.2 | 0.6 0.1 0.5–0.7 |
Nb5Si3 | 46.7 0.2 46.4–47.0 | 8.2 0.3 8.1–8.6 | 32.5 0.7 31.4–33.2 | 4.3 0.1 4.2–4.4 | 0.7 0.1 0.6–0.8 | 1.0 0.1 0.9–1.1 | 6.0 0.2 5.9–6.2 | 0.6 0.2 0.4–0.7 |
Ti–rich Nb5Si3 | 44.0 1.1 42.1–45.1 | 13.0 1.2 12.2–15.2 | 29.2 0.8 28.3–30.4 | 3.1 0.4 2.3–3.4 | 0.2 | 1.9 0.4 1.5–2.5 | 7.6 0.6 7.1–8.7 | 1.0 0.1 0.9–1.2 |
A15 | 56.5 0.9 55.4–57.8 | 16.8 1.3 15.0–18.5 | 6.6 0.5 5.8–7.1 | 4.7 0.5 4.0–5.2 | 2.2 0.4 1.7–2.7 | 9.5 0.4 8.9–10.0 | 3.1 0.2 2.9–3.4 | 0.6 0.2 0.3–0.9 |
Eutectic | 53.2 0.9 52.2–54.3 | 13.5 0.6 12.9–14.3 | 15.6 0.4 15.1–16.1 | 5.9 0.1 5.9–5.9 | 3.0 0.2 2.9–3.0 | 3.4 0.2 3.2–3.6 | 4.3 0.2 4.2–4.6 | 1.1 0.3 0.8–1.6 |
Heat-treated | ||||||||
Large area | 51.0 0.6 50.3–51.8 | 12.0 0.3 11.8–12.5 | 21.1 1.1 19.5–22.6 | 5.4 0.3 4.9–5.8 | 2.1 0.2 1.8–2.2 | 2.7 0.1 2.7–2.8 | 4.9 0.2 4.6–5.2 | 0.8 0.1 0.7–0.8 |
Nbss | 65.6 0.3 65.3–66.2 | 10.7 0.4 10.4–11.3 | 3.5 1.0 2.5–4.9 | 10.0 0.4 9.5–10.4 | 7.5 0.2 7.3–7.7 | 2.2 0.2 1.9–2.4 | 0.5 0.1 0.4–0.6 | 0 |
Nb5Si3 | 46.7 0.4 46.2–47.1 | 8.4 0.5 7.9–9.1 | 32.3 0.7 31.2–32.8 | 4.6 0.2 4.4–4.8 | 0.7 0.3 0.2–0.9 | 0.8 0.1 0.8–1.0 | 5.9 0.2 5.6–6.1 | 0.6 0.1 05–0.7 |
Ti–rich Nb5Si3 | 37.9 4.6 34.3–43.3 | 19.4 4.6 14.3–22.8 | 28.6 2.4 26.5–31.8 | 2.6 0.3 2.2–2.9 | 0 | 0.7 0.4 0.2–1.2 | 9.3 2.1 6.8–10.9 | 1.5 0.6 0.7–2.2 |
A15 | 58.8 0.4 58.3–59.4 | 14.5 0.3 14.2–14.8 | 5.7 0.6 5.2–6.6 | 5.3 0.2 4.9–5.4 | 2.3 0.1 2.2–2.5 | 10.4 0.2 10.2–10.7 | 2.9 0.1 2.7–3 | 0 |
Alloy | 800 °C | 1200 °C | |||
---|---|---|---|---|---|
Weight Gain (mg/cm2) | Rate Constant | Weight Gain (mg/cm2) | Rate Constant | ||
kl (g cm−2 s−1) | kl (g cm−2 s−1) | kp (g2 cm−4 s−1) | |||
JZ1 | 33.6 (100 h) | 1.14 10−7 (0–58 h) 7.5 10−8 (58−100 h) | 91.3 (100 h) | 2.16 10−7 (9–100 h) | 1.4 10−8 (0–9 h) |
JZ2 | 28.9 (100 h) | 1 10−7 (0–53 h) 6.8 10−8 (53–100 h) | 71.7 (100 h) | 1.8 10−7 (9–100 h) | 5.5 10−9 (0–9 h) |
Area | Phase | O | Nb | Ti | Si | Ta | W | Sn | Ge | Hf |
---|---|---|---|---|---|---|---|---|---|---|
Oxide scale | Nb-rich oxide | 74.4 0.7 73.3–75.0 | 16.6 0.9 15.6–17.7 | 5.7 1.9 3.6–7.5 | 0.7 0.5 0.3–1.4 | 1.8 0.4 1.3–2.3 | 0.4 0.2 0.3–0.7 | – | – | 0.3 0.2 0.2–0.6 |
Ti–rich oxide | 73.8 0.8 72.8–74.6 | 4.0 0.7 3.5–5.2 | 20.9 0.9 19.7–22.2 | 0.3 0.2 0.1–0.5 | 0.6 0.1 0.6–0.7 | – | – | – | 0.4 0.1 0.3–0.4 | |
HfO2 | 71.8 1.7 69.7–73.2 | 1.6 0.4 1.2–1.9 | 1.1 0.1 1.0–1.1 | 0.5 0.9 0–1.6 | – | – | – | – | 24.9 0.3 24.6–25.1 | |
Diffusion zone 1 | Nb5(Si1–x,Gex)3 | - | 54.3 0.9 52.8–54.8 | 1.6 0.6 1.1–2.7 | 15.3 0.5 14.6–15.7 | 5.2 0.3 4.7–5.4 | 1.1 0.2 0.9–1.4 | - | 22.4 1.0 21.6–24.1 | - |
W–rich Nb5(Si1–x,Gex)3 | - | 47.4 1.2 45.7–48.7 | 1.2 0.2 1.0–1.5 | 12.8 1.0 12.2–14.6 | 7.4 0.3 7.2–7.9 | 6.2 0.5 5.7–6.9 | 0.5 0.4 0.3–1.0 | 24.8 1.5 22.7–26.6 | - | |
NbGe2 | - | 33.0 0.9 32.0–34.1 | 1.0 0.5 0.2–1.4 | 4.4 1.2 2.8–5.8 | 2.7 0.4 2.3–3.4 | 0.9 0.3 0.6–1.5 | 0.2 0.1 0.1–0.4 | 57.8 1.0 56.5–5.89 | - | |
Diffusion zone 2 | Nb5Si3 | - | 48.3 0.3 47.8–48.7 | 8.0 0.2 7.6–8.2 | 31.4 0.7 30.7–32.4 | 4.5 0.3 4.1–4.9 | 0.7 0.1 0.6–0.9 | 1.0 0.1 0.9–1.1 | 5.5 0.2 5.3–5.7 | 0.6 0.2 0.5–0.9 |
Ti–rich Nb5Si3 | - | 45.8 1.2 44.1–46.6 | 15.0 1.8 13.7–17.7 | 24.9 0.6 24.2–25.6 | 3.4 0.5 2.7–3.7 | 0.3 0.1 0.2–0.4 | 3.2 0.4 2.8–3.7 | 6.8 0.5 6.3–7.4 | 0.9 0.1 0.7–1.0 | |
A15 | - | 61.0 0.8 59.9–61.9 | 14.2 1.0 12.9–15.4 | 4.7 0.9 3.7–5.7 | 4.6 0.3 4.2–4.9 | 2.0 0.4 1.4–2.5 | 10.3 0.3 10.0–10.8 | 3.2 0.1 3.1–3.3 | - | |
Nbss a | - | 69.7 | 5.5 | 4.6 | 10.2 | 7.1 | 2.0 | 0.8 | 0.2 | |
Bulk | Nb5Si3 | - | 47.0 1.0 45.9–48.3 | 8.2 0.2 8.1–8.6 | 31.9 0.8 30.9–32.7 | 4.6 0.3 4.2–5.0 | 0.7 0.10 0.6–0.8 | 1.0 0.1 0.9–1.1 | 5.9 0.5 5.3–6.4 | 0.7 0.1 0.5–0.8 |
Ti–rich Nb5Si3 | - | 42.9 1.5 40.6–44.6 | 17.0 2.2 13.8–19.4 | 26.2 0.9 25.0–27.3 | 2.9 0.6 2.4–3.9 | – | 2.4 0.4 1.8–2.9 | 7.6 0.7 6.5–8.6 | 1.1 0.1 1.0–1.3 | |
A15 | - | 58.9 0.9 57.2–59.3 | 16.6 0.5 16.2–17.3 | 3.9 1.0 3.1–5.5 | 5.0 0.4 4.6–5.6 | 2.0 0.2 1.8–2.2 | 10.8 0.5 10.4–11.7 | 2.8 0.2 2.4–2.9 | - | |
Nbss | - | 66.1 1.0 64.9–67.5 | 10.3 0.4 9.7–10.7 | 3.9 1.4 2.1–5.4 | 10.1 0.5 9.6–10.9 | 6.8 0.5 6.2–7.3 | 1.9 0.6 1.2–2.7 | 1.0 0.3 0.6–1.3 | - |
Theory * | Element | ||||
---|---|---|---|---|---|
A | Si | Sn | Ge | Hf | Ti |
B | - | Sn | Ge | - | Ti |
C | Si | Sn | Ge | - | - |
D | Si | Sn | Ge | Hf | Ti |
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Zhao, J.; Utton, C.; Tsakiropoulos, P. On the Microstructure and Properties of Nb-12Ti-18Si-6Ta-2.5W-1Hf (at.%) Silicide-Based Alloys with Ge and Sn Additions. Materials 2020, 13, 1778. https://doi.org/10.3390/ma13071778
Zhao J, Utton C, Tsakiropoulos P. On the Microstructure and Properties of Nb-12Ti-18Si-6Ta-2.5W-1Hf (at.%) Silicide-Based Alloys with Ge and Sn Additions. Materials. 2020; 13(7):1778. https://doi.org/10.3390/ma13071778
Chicago/Turabian StyleZhao, Jiang, Claire Utton, and Panos Tsakiropoulos. 2020. "On the Microstructure and Properties of Nb-12Ti-18Si-6Ta-2.5W-1Hf (at.%) Silicide-Based Alloys with Ge and Sn Additions" Materials 13, no. 7: 1778. https://doi.org/10.3390/ma13071778