Cavity-Back Fan Blade Diffusion Bonding With Low-Distortion Fixturing
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Solution Overview
Problem
The manufacturing of hollow titanium fan blades for gas turbine engines is challenging due to high equipment and material investments, limited throughput, and yield, as well as degradation of ductility and fatigue strength through fusion welding.
Innovation Solution
A fixture assembly and method for diffusion bonding the periphery of a cavity-back fan blade, which includes a first and second fixture portion with actuators and a sub-fixture for precise pressure and temperature control, allowing for enhanced bonding at lower temperatures and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fusion welding is used to join fan blade components, then joining strength is achieved, but ductility and fatigue strength are degraded
Solution Approach 1:
The invention changes the bonding parameters from high-temperature fusion welding to low-temperature diffusion bonding (below recrystallization temperature). This parameter change enables joining while preserving the material's ductility and fatigue strength by avoiding the thermal damage and microstructural degradation associated with fusion welding.
Solution Approach 2:
The invention replaces the mechanical fusion welding process with a diffusion bonding process that relies on atomic diffusion and creep mechanisms at lower temperatures. This substitution eliminates the harmful thermal cycles and molten pool formation that degrade mechanical properties in fusion welding.
2Ease of manufacture
If conventional diffusion bonding is used for hollow fan blades, then high-temperature alloy components with complex geometries can be manufactured, but substantial equipment investment and limited throughput are required
Solution Approach 1:
The invention segments the bonding process into multiple zones along the periphery of the airfoil, with each zone independently controllable. This allows parallel processing and reduces overall cycle time, thereby increasing throughput while maintaining manufacturing capability for complex geometries.
Solution Approach 2:
The invention introduces dynamic control of heating and pressing during diffusion bonding, allowing real-time adjustment of process parameters. This dynamic approach optimizes bonding efficiency and reduces cycle time, improving throughput without sacrificing the ability to manufacture complex geometries.
3Device complexity
If diffusion bonding is performed without precise control, then manufacturing process is simpler, but bonding quality and mechanical properties are compromised
Solution Approach 1:
The invention incorporates feedback control systems that monitor temperature, pressure, and bonding progress in real-time. This feedback enables precise control of the diffusion bonding process, ensuring high bonding quality and mechanical properties while maintaining relatively simple process equipment through intelligent control algorithms.
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 solution enables the production of high-quality, hollow titanium fan blades with improved mechanical properties, reduced environmental impact, and lower costs by minimizing complex processes and equipment needs.
Implementation Method 1
diffusion bonding the periphery of a cavity-back airfoil
Implementation Method 2
actuators and a sub-fixture for precise pressure and temperature control
Implementation Method 3
allowing for enhanced bonding at lower temperatures and reducing distortion
Data Source
Figure 1
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AI summary
A fixture assembly 200 includes a first fixture portion 202, a second fixture portion 204 that interfaces with the first fixture portion 202, and a sub-fixture 206 movably mounted to the first fixture portion 202. A multiple of actuators (208) selectively move the sub-fixture 206 toward the second fixture portion 204. A method of manufacturing a fan blade (58) includes deploying the sub-fixture 206 from the first fixture portion 202 to effectuate a peripheral diffusion bond to join the blade body (80) and the cover (82) of the fan blade (58).