TiAl Rotor Blade Alloy Composition for Complex Casting Yield
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Solution Overview
Problem
Conventional TiAl alloy cast materials suffer from poor molten alloy flowability, leading to defective shapes and low non-defective product yield, particularly in complex turbine blades for jet engines, and lack adequate impact resistance, high-temperature strength, and oxidation resistance.
Innovation Solution
A TiAl alloy composition comprising specific ranges of aluminum, manganese, iron, vanadium, and niobium, with optional carbon, optimized for improved castability, impact resistance, high-temperature strength, and oxidation resistance, produced using methods like investment casting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional TiAl alloy composition is used for casting, then the alloy can be produced, but the molten alloy flowability is insufficient leading to defective shapes
Solution Approach 1:
The patent applies parameter changes by optimizing the chemical composition of the TiAl alloy within specific ranges: Al-45.5-47.5 atom%, Mn-1.0-3.0 atom%, Fe-0.3-1.0 atom%, V-0.5-2.0 atom%, and Nb-0.5-2.5 atom%. These compositional parameters are carefully controlled to simultaneously improve molten alloy flowability for complete cavity filling and maintain adequate impact resistance, resolving the contradiction between castability and reliability.
2Ease of manufacture
If investment casting method is used to produce turbine blades, then the amount of machining is reduced, but the castability is insufficient due to poor molten alloy flowability
Solution Approach 1:
The patent resolves this contradiction by changing the compositional parameters of the TiAl alloy to enhance molten alloy flowability. The optimized composition enables complete filling of complex turbine blade cavities during investment casting, achieving high non-defective product yield and reducing machining requirements while maintaining manufacturing precision.
Solution Approach 2:
The patent employs composite material principles by creating a multi-element TiAl alloy system incorporating Mn, Fe, V, and Nb in specific proportions. This composite alloy composition synergistically improves both flowability for complex shape casting and mechanical properties, enabling successful investment casting of turbine blades with minimal post-processing.
3Weight of moving object
If TiAl alloy is used instead of Ni-based superalloys, then the weight is reduced improving engine efficiency, but the impact resistance and high-temperature strength are insufficient
Solution Approach 1:
The patent applies composite material principles by developing a multi-element TiAl alloy incorporating Mn, Fe, V, and Nb. This composite composition maintains the lightweight advantage of TiAl alloys while synergistically enhancing impact resistance and high-temperature strength through the combined effects of different alloying elements, resolving the contradiction between weight reduction and strength requirements.
Solution Approach 2:
The patent applies local quality principles by strategically distributing different alloying elements within the TiAl matrix to achieve localized property enhancements. The specific composition ranges enable different regions of the alloy structure to contribute to either weight reduction, impact resistance, or high-temperature strength as needed, optimizing overall performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optimized TiAl alloy achieves high non-defective product yield, excellent impact resistance, high-temperature strength, and oxidation resistance, making it suitable for turbine blades with reduced machining needs.
Implementation Method 1
rotating the mold at a high speed together with the internal molten alloy, and applying a centrifugal force to the molten alloy to perform casting
Implementation Method 2
excellent impact resistance, high-temperature strength, and oxidation resistance
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
A TiAl alloy material contains aluminum: 45.5 to 47.5 atom%, manganese: 1.0 to 3.0 atom%, iron: 0.3 to 1.0 atom%, vanadium: 0.5 to 2.0 atom%, and niobium: 0.5 to 2.5 atom%, with the remainder being made up of titanium and unavoidable impurities. The TiAl alloy material may further contain carbon: 0.6 atom% or less.