Gamma Prime Nickel Superalloy for Crack-Free Turbine Welding
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Solution Overview
Problem
Current high gamma prime nickel-based superalloys used for turbine engine components face challenges with weldability, creep properties, and microcracking, particularly in repair and 3D additive manufacturing, due to limitations in oxidation resistance, ductility, and mechanical properties at elevated temperatures.
Innovation Solution
A high gamma prime nickel-based superalloy with specific chemical composition (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 1.5-3.5% Re, with optimized heat treatment processes including annealing and aging, is developed to enhance weldability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cobalt based M72 welding material is used, then weldability and oxidation resistance are improved, but creep properties deteriorate at temperatures ≥1800°F
Solution Approach 1:
The invention changes the chemical composition parameters by limiting cobalt content to 5-15 wt.% (down from typical high cobalt formulations) and optimizing other alloying elements including 5-25 wt.% Cr, 1-6 wt.% Al, and specific amounts of W, Mo, Ta, Re, Hf, Ti, Zr, and B. This parameter optimization resolves the contradiction by achieving both good weldability and creep resistance at high temperatures without requiring excessive cobalt content.
Solution Approach 2:
The welding material creates a composite microstructure with gamma (γ) matrix phase and gamma prime (γ') precipitates through controlled alloying. The combination of multiple alloying elements (Cr, Al, W, Mo, Ta, Re, Hf, Ti, Zr, B) forms a complex composite material that simultaneously provides oxidation resistance, creep strength, and weldability, resolving the trade-off between these properties.
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 reduces gamma prime (γ') precipitate content to 10-30 vol.% (lower than conventional high γ' formulations) and optimizes the matrix phase composition with controlled amounts of alloying elements. This parameter adjustment improves ductility and weldability while maintaining adequate creep properties through the optimized matrix phase, resolving the contradiction between strength and weldability.
Solution Approach 2:
The invention creates different local microstructural zones: a ductile gamma (γ) matrix phase for weldability and controlled γ' precipitates for creep resistance. The local quality varies through the microstructure with the matrix providing ductility for crack-free welding while the precipitates provide high-temperature strength, resolving the contradiction between weldability and creep properties.
3Reliability
If preheating to high temperature is applied for R142 welding, then weldability is improved, but process complexity and energy consumption increase
Solution Approach 1:
The invention uses a disposable welding material formulation that inherently provides good weldability at ambient temperature without requiring complex preheating equipment or processes. The optimized composition (5-15 wt.% Co, 5-25 wt.% Cr, 1-6 wt.% Al, etc.) enables direct welding, eliminating the need for expensive and complex preheating infrastructure, thus resolving the contradiction between weldability and process complexity.
Solution Approach 2:
The invention changes the material parameters (chemical composition and microstructure) to enable welding at ambient temperature conditions. By optimizing the matrix phase composition and controlling γ' precipitate content, the material achieves sufficient ductility and crack resistance without thermal preheating, simplifying the welding process and reducing energy consumption while maintaining weldability.
4Reliability
If nickel based superalloys with elevated Co content (20-30%) are used, then weldability is improved, but mechanical properties at ≥1800°F deteriorate
Solution Approach 1:
The invention optimizes the cobalt content parameter to a moderate range of 5-15 wt.% (avoiding both low and excessive cobalt content) and balances it with other alloying elements (Cr: 5-25 wt.%, W: 1-20 wt.%, Mo: 1-6 wt.%, Ta: 1-18 wt.%, Re: 1-3 wt.%). This balanced parameter optimization achieves good weldability without the high-temperature mechanical property deterioration associated with 20-30% cobalt formulations.
Solution Approach 2:
The invention creates a composite alloy system where moderate cobalt content (5-15 wt.%) works synergistically with chromium, tungsten, molybdenum, tantalum, rhenium, and other elements. This multi-element composite material provides a balanced combination of weldability, oxidation resistance, and high-temperature mechanical properties, resolving the contradiction between weldability and mechanical strength at elevated temperatures.
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 new superalloy achieves excellent weldability, high strength, ductility, and oxidation resistance, producing crack-free welds at ambient temperature, suitable for various repairs and manufacturing processes, including 3D additive manufacturing and hot forming, with superior mechanical properties compared to existing alloys.
Implementation Method 1
The invention relates to a high gamma prime (γ') nickel-based superalloy... that has excellent weldability at an ambient temperature, good combination of mechanical and oxidation properties
Implementation Method 2
nickel based superalloys used for turbine engine components face challenges with weldability, creep properties, and microcracking, particularly in repair and 3D additive manufacturing, due to limitations in oxidation resistance
Data Source
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Figure 2a~2b
Figure 3a~3b
AI summary
The invention is related 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.