Gas Turbine Component Repair Using Solid-State Sintered Replacement Pieces
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Solution Overview
Problem
The additive manufacturing of nickel-base gas turbine components with high gamma prime content is challenging due to grain boundary melting and cracking issues, making large-scale manufacturing or repair unsuitable, and using inferior alloys results in poor performance.
Innovation Solution
A method involving mixing powdered base material with a binder to form a near-net shape without melting, followed by binder removal, solid-state sintering, and infiltration with a melting point depressant to achieve a component with less than 1% porosity, allowing for the repair of damaged components with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additive manufacturing is used to manufacture nickel-base gas turbine components with high gamma prime content, then the components can be produced with complex geometries and customized designs, but grain boundary melting and cracking occur resulting in poor reliability
Solution Approach 1:
The invention changes the fundamental manufacturing parameter from melting-based additive manufacturing to solid-state processes. By using solid-state sintering and diffusion bonding, the process avoids the melting point entirely, eliminating grain boundary melting and cracking while maintaining the ability to manufacture complex geometries and customized designs
Solution Approach 2:
The invention replaces the thermal-melting mechanism with solid-state physical-chemical processes. Instead of using heat to melt and fuse metal particles, the process uses sintering and diffusion bonding mechanisms that occur below the melting point, substituting a mechanical/diffusion-based system for a melting-based system
2Ease of repair
If conventional additive manufacturing processes are used to repair gas turbine components, then damaged portions can be replaced, but the repair areas are prone to cracking and have poor mechanical properties
Solution Approach 1:
The invention changes the processing parameters by maintaining temperatures below the melting point throughout the repair process. Solid-state sintering and diffusion bonding are performed at temperatures that activate atomic diffusion and bonding mechanisms without causing grain boundary melting, eliminating cracking while enabling effective repair of damaged portions
Solution Approach 2:
The invention applies preliminary protective measures by using a coating material containing melting point depressants during the sintering process. This coating prevents grain boundary melting and cracking during heating, ensuring the repair area achieves high mechanical strength without defects
3Reliability
If inferior nickel base alloys are used to repair components, then cracking is reduced, but the component performance deteriorates
Solution Approach 1:
The invention applies local quality by using different materials in different regions. The base component uses high gamma prime content nickel-base alloy for optimal performance, while the repair area uses a composite structure with sintered powder and melting point depressant coating. This local differentiation allows the repair area to achieve crack resistance without compromising the overall component performance
Solution Approach 2:
The invention creates a composite material structure in the repair area consisting of sintered nickel-base alloy powder particles bonded together and coated with melting point depressant material. This composite structure provides both crack resistance and high mechanical properties, superior to using inferior alloys alone
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
This approach enables the repair of gas turbine components with reduced porosity and enhanced mechanical properties, preventing cracking and improving oxidation resistance, thus addressing the limitations of existing repair methods.
Implementation Method 1
removing the binder from the green form component, thereby forming a porous skeleton structure
Implementation Method 2
The sintered component is then heated to a temperature below the melting point of the base material for a period of time to react a majority of the braze material with the base material powder
Implementation Method 3
to react a majority of the braze material with the base material powder
Implementation Method 4
The sintered component is then heated to a temperature below the melting point of the base material for a period of time to react a majority of the braze material with the base material powder
Data Source
AI summary
A method of repairing a component includes removing a damaged portion from the component to leave a first interface surface that is defined by a continuous curve, mixing a powdered base material and a binder to define a mixture, and printing the mixture into a desired shape without melting the base material. The method also includes removing the binder from the desired shape, solid-state sintering the desired shape to form a replacement piece having a second interface surface that is defined by the continuous curve, and attaching the second interface surface to the first interface surface to replace the damaged portion of the component.