Turbine Blade Leading Edge Repair Using FAST Diffusion Bonding
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Solution Overview
Problem
Conventional turbine blade repair techniques are unable to restore lost wall thickness at high-stress regions like the leading edge, limiting the number of repairs possible and leading to early engine overhaul.
Innovation Solution
The method employs Field Assisted Sintering Technology (FAST) to join an airfoil with a component, forming a blade by heating and applying mechanical pressure, allowing for the restoration of the leading edge by machining and coupling the airfoil with a component made of similar or dissimilar metal alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional repair techniques are used, then the blade can be maintained for operation, but the lost wall thickness in high-stress regions cannot be restored
Solution Approach 1:
The repair process segments the blade restoration into distinct phases: removing damaged material to create a mating surface, fabricating a separate replacement component with the required geometry and material properties, and joining them through FAST. This allows the lost wall thickness to be restored through component addition rather than attempting to rebuild the original continuous structure.
Solution Approach 2:
The invention changes the physical parameters of the materials involved by heating both the airfoil and replacement component to elevated temperatures (typically 100-500°C) and applying high pressure (typically 10-1000 MPa) during the FAST process. These parameter changes enable solid-state diffusion bonding that restores the mechanical properties and wall thickness equivalent to the original intact blade structure.
2Productivity
If conventional repair techniques are used, then the blade can be maintained, but the number of repairs is limited to 1-3 before overhaul is required
Solution Approach 1:
By changing the physical state and properties of materials through controlled heating and pressurization in the FAST process, the invention creates a repair method that fully restores the blade's structural integrity and material properties. This allows the blade to return to near-as-new condition, enabling multiple repair cycles rather than the limited 1-3 repairs possible with conventional techniques that cannot restore lost thickness.
Solution Approach 2:
The repair creates a composite structure where the replacement component (made from appropriate metal alloys matching or exceeding the original material) is bonded to the remaining airfoil structure. This composite construction, joined through solid-state diffusion bonding, achieves strength and durability equivalent to monolithic structures, allowing repeated repairs without degradation of service life.
3Reliability
If the leading edge distress becomes severe, then the engine must be taken off-wing for repair or overhaul, but replacement parts are expensive
Solution Approach 1:
Instead of discarding the entire blade when the leading edge becomes damaged, the invention removes only the distressed portion and replaces it with a new component. The remaining sound portions of the airfoil are retained and reused, recovering significant material value and avoiding the expense of complete blade replacement while restoring full structural integrity.
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 multiple repairs of turbine blades by restoring the leading edge wall thickness, reducing replacement costs and extending engine life.
Implementation Method 1
heating, via the FAST system, the airfoil and the component
Implementation Method 2
heating, via the FAST system, the airfoil and the component
Implementation Method 3
applying, via the FAST system, a mechanical pressure between the first mating surface and the second mating surface to join the airfoil to the component
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A method can comprise forming a component (610) comprising a first mating surface (602); coupling the component (610) to an airfoil (202) having a second mating surface (612) and a Field Assisted Sintering Technology ("FAST") system; heating, via the FAST system, the airfoil (202) and the component (610) ; and applying, via the FAST system, a mechanical pressure between the first mating surface (602) and the second mating surface (612) to join the airfoil (202) to the component (610) and form a blade (650), the component (610) at least partially defining a leading edge (204) of the blade (650) in response to joining the airfoil (202) to the component (610).