Mechanical Interlock Brazed Joints for Complex Cast Components
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Solution Overview
Problem
Casting large or complex metal or alloy components, such as nozzle guide vanes for gas turbine engines, often results in high rejection rates due to defects and limitations in design complexity, as traditional methods require complex and costly processes like bi-casting that can lead to integrity issues and high leakage.
Innovation Solution
A technique involving the use of a braze material that forms a mechanical interlock between components without metallurgical bonding, utilizing an adhesion-resistant material to prevent adherence and employing pre-sintered preform braze alloys that can be heated to form a softened state conforming to the joint region, then cooled to secure the components with reduced porosity and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional casting methods are used to form large or complex metal components, then manufacturing capability is maintained, but defect rates increase and design complexity is restricted
Solution Approach 1:
The invention divides a large or complex component into multiple separate sub-components that can be cast with simpler geometries and lower defect rates. These sub-components are then joined together using mechanical interlocking features (such as recesses and protrusions) rather than traditional metallurgical bonding, enabling complex overall designs while maintaining manufacturing precision of individual segments.
2Device complexity
If bi-casting process is used to form complex geometries, then design complexity is improved, but process complexity and cost increase
Solution Approach 1:
Instead of using complex bi-casting processes to create complex geometries, the invention segments the component into multiple separately-cast sub-components with simpler geometries. These segments are then assembled using mechanical interlocking features, significantly reducing process complexity and cost while achieving the desired overall geometric complexity.
Solution Approach 2:
The invention introduces mechanical interlocking features (recesses and protrusions) as intermediary elements between sub-components. These features serve as mediators that connect separately-cast components without requiring complex metallurgical bonding processes, thereby simplifying manufacturing while enabling complex assembled geometries.
3Ease of manufacture
If traditional joining methods are used to assemble components, then assembly capability is maintained, but leakage increases
Solution Approach 1:
The invention introduces mechanical interlocking features (interlocking recesses and protrusions) as intermediary connection elements between components. These features provide precise geometric alignment and physical interlocking that prevents leakage paths, achieving reliable sealed connections while maintaining ease of assembly through straightforward mechanical engagement rather than complex bonding processes.
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 method reduces defect rates, allows for more complex geometries, and provides a low-leakage structural connection suitable for high-temperature environments, while maintaining component integrity and reducing manufacturing costs by enabling batch processing of multiple components.
Implementation Method 1
heating the braze material to a processing temperature to form an at least softened material in the joint region
Implementation Method 2
cooling the at least softened material to form a mechanical interlock including the braze material in the joint region joining the first and second components
Implementation Method 3
An adhesion resistant material present between the braze material and the joint surface. The adhesion resistant material is configured to resist adherence of the braze material to the joint surface
Data Source
AI summary
The disclosure describes example techniques and assemblies for joining a first component and a second component. The techniques may include positioning the first and second component adjacent to each other to define a joint region between adjacent portions of the first component and the second component, the joint region being coated with an adhesion resistant coating. The techniques may also include positioning a braze material in the joint region, heating the braze material to form an at least softened material, and cooling the at least softened material to form a mechanical interlock including the braze material in the joint region joining the first and second components. The braze material does not metallurgically bond to the joint surface.