High Gamma Prime Superalloy Composition for Crack-Free Turbine Welding
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Solution Overview
Problem
Current high gamma prime nickel-based superalloys face challenges in achieving crack-free welds with good mechanical and oxidation properties at ambient temperatures, particularly for repairing and 3D additive manufacturing of turbine engine components, due to limitations in weldability, creep resistance, and microcracking issues with existing materials like René 142 and Merl 72.
Innovation Solution
A high gamma prime nickel-based superalloy with specific compositions (9.0-10.5% Cr, 16-22% Co, 1.0-1.4% Mo, 5.0-5.8% W, 2.0-6.0% Ta, 3.0-7.0% total Ta and Nb, 3.0-6.5% Al, 0.2-1.5% Hf, 0.01-0.2% C, 0-1.0% Ge, 0-0.2% Si, 0-0.015% B, and nickel balancing, which exhibits excellent weldability and a combination of mechanical and oxidation resistance, suitable for fusion welding, casting, and 3D additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cobalt based M72 welding material is used for repair of turbine blades, then weldability and oxidation resistance are improved, but creep properties deteriorate at temperatures ≥1800°F
Solution Approach 1:
The invention uses a composite welding material composition containing Ni-9Cr-10Co-1Mo-5.5W-5Ta-5.5Al-0.5Hf-0.1C-0.01B (in wt.%) that combines the advantages of both cobalt-based and nickel-based superalloys. This composite material achieves excellent weldability like M72 while providing superior creep resistance comparable to or better than R142, resolving the contradiction between weldability and high-temperature creep strength.
2Strength
If high γ′ nickel based R142 welding wire is used, then creep properties are improved, but weldability deteriorates with poor ductility and high propensity to microcracking
Solution Approach 1:
The invention modifies the chemical composition parameters of nickel-based superalloys by precisely controlling the content of alloying elements: Cr (9-10%), Co (10-12%), Mo (1-1.5%), W (5-5.8%), Ta (5-6%), Al (5-6.5%), and adding Hf (0.5-1.5%). These parameter changes optimize both the γ′ phase precipitation for creep resistance and the matrix ductility for weldability, eliminating microcracking while maintaining high-temperature strength.
3Ease of manufacture
If nickel based superalloy R80 is used for welding, then weldability is improved, but oxidation resistance deteriorates
Solution Approach 1:
The invention applies local quality by creating a optimized chemical composition with specific ranges of oxidation-resistant elements: Cr (9-10%) and Al (5-6.5%) concentrated in the welding material to provide excellent oxidation resistance at the weld zone, while maintaining good weldability through balanced Co (10-12%) and Ta (5-6%) content. This localized optimization of element distribution resolves the contradiction between weldability and oxidation resistance.
Data Source
AI summary
The specification relates to a high gamma prim nickel based superalloy, its use and a method of manufacturing of turbine engine components by welding, 3D additive manufacturing, casting and hot forming, and the superalloy comprises by wt %: from 9.0 to 10.5% Cr, from 16 to 22% Co, from 1.0 to 1.4% Mo, from 5.0 to 5.8% W, from 2.0 to 6.0% Ta, from 1.0 to 4.0% Nb provided that total content of Ta and Nb remains with a range from 3.0 to 7.0%, from 3.0 to 6.5% Al, from 0.2 to 1.5% Hf, from 0.01 to 0.2% C, from 0 to 1.0% Ge, from 0 to 1.0 wt. % Si, from 0 to 0.2 wt. % Y, from 0 to 0.015 wt. % B, from 1.5 to 3.5 wt. % Re, and nickel with impurities to balance.