1. Introduce
– Second-generation single crystal superalloy with about 3% added Re
* Single crystal superalloys
- Superalloy developed to increase creep resistance and temperature acceptance by minimizing the grain boundary
- The addition of grain boundary strengthening elements such as C, B, Zr, and Hf suppresses grain boundary formation and allows heat treatment at higher temperatures to increase the fraction of γ′ phase and improve microstructure uniformity
- Large amounts of refractory alloying elements such as W, Ta, and Mo are added to optimize the mechanical properties of single crystal alloys
- Representative first-generation single crystal superalloys : Rene N4, CMSX-2, CMSX-3, CMSX-6, PWA1480, etc.
- Representative second generation single crystal superalloys : Rene N5, PWA 1484, CMSX-4, etc.
- Representative 3rd generation single crystal superalloys : Rene N6, CMSX-10, etc.
* Re
- The most important added element in the development of single crystal alloys
- Role in improving the temperature acceptance of alloys
- When added in large amounts, it forms a secondary reaction zone with the TCP phase, resulting in microstructural instability of the alloy and deterioration of alloy properties at high temperature
- Freckle defects are more likely to form when added in large quantities, but can be suppressed by increasing the content of Ta
* TCP phase (Topologicalloy Closed Packed Phase)
- TCP phases such as σ, μ, P phase tend to form when exposed to high temperature for a long time
- Brittle organization, mechanical properties such as creep life, ductility, impact strength, etc. decrease as the content in the base increases
- The tendency of precipitation of TCP phase increases slightly when the content of refractory elements such as Re, Mo, and W is high
2. Property
– Excellent creep properties, thermal fatigue properties, oxidation resistance, etc.
| Element | Impact |
|---|---|
| Ni | Provides excellent strength and corrosion resistance |
| Cr | Provides high temperature corrosion resistance |
| Co | Provides strength, creep properties |
| W | Highly strengthening element, provides high temperature creep properties |
| Ta | Provides strength, fraction of γ′ phase |
| Re | Tensile strength at high temperature, creep characteristics |
[Rene N5 Chemical Composition (%)]
| Ni | Cr | Al | Mo | Co |
|---|---|---|---|---|
| Min. 61.60 | Max. 7.00 | Max. 6.20 | Max. 2.00 | Max. 8.00 |
| W | Ta | Re | Hf | |
|---|---|---|---|---|
| Max. 5.00 | Max. 7.00 | Max. 3.00 | Max. 0.20 |
3. Available Form
– Bar, Rod
– Sheet, Plate
– Wire, Coil
4. Application & Product
– Aerospace
| Application | Product |
|---|---|
| Aerospace | Gas turbine blades, Airfoils |

(1) Gas turbine blades / (2) Airfoils


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