Intermediate Component Brazing for Dissimilar CTE Joints
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Solution Overview
Problem
Conventional brazing methods for components with dissimilar coefficients of thermal expansion result in strains due to differential expansion and contraction, limiting design flexibility and potentially causing damage at the brazed interface, especially at higher temperatures or greater material CTE differences.
Innovation Solution
A method involving the use of an intermediate component with a coefficient of thermal expansion between the first and second components, where braze materials are deposited and fitted at room temperature, allowing for simultaneous or sequential heating to form braze joints, utilizing alloys like nickel, precious metals, or copper-based materials with varying melting temperatures to minimize strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brazing methods are used to join components with dissimilar coefficients of thermal expansion, then the brazing operation can be performed, but strains are generated due to differential expansion and contraction that can result in damage along the brazed interface
Solution Approach 1:
The patent introduces an intermediate component with a coefficient of thermal expansion between that of the first and second components. This intermediate component acts as a mediator that gradually transitions the thermal expansion properties between the two dissimilar materials, reducing the abrupt strain at the brazed interface and preventing damage while maintaining joint integrity.
2Strength
If higher brazing temperatures are used to improve joint strength, then the brazing operation can be completed more effectively, but the strains due to differential thermal expansion become more severe
Solution Approach 1:
The intermediate component serves as a thermal buffer that allows the use of higher brazing temperatures to achieve strong joints while mitigating the severe thermal strains that would otherwise occur between dissimilar materials with different coefficients of thermal expansion.
3Adaptability or versatility
If components with dissimilar coefficients of thermal expansion are joined, then design flexibility is increased, but the difference in CTE between materials creates strains that limit design choices
Solution Approach 1:
The intermediate component enables designers to join materials with dissimilar coefficients of thermal expansion by providing a gradual transition zone. This resolves the CTE mismatch strain issue while preserving design flexibility, allowing a broader range of material combinations and design configurations.
Solution Approach 2:
The patent changes the thermal expansion parameter by introducing an intermediate component with a specific coefficient of thermal expansion that lies between those of the first and second components. This parameter adjustment reduces the strain caused by CTE mismatch while maintaining design versatility.
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 reduces strain and allows for the assembly of components with dissimilar thermal expansion coefficients at room temperature, enhancing the manufacturing process for structures like turbine engines by creating multiple braze joints with reduced stress and improved reliability.
Implementation Method 1
heating the first component and intermediate component prior to depositing the second braze material to melt the first braze material and form a first braze joint
Implementation Method 2
because parts made of different materials will usually have different coefficients of thermal expansion (CTE), the two parts will expand by different amounts when subjected to the heat of the brazing operation
Data Source
AI summary
A method of manufacturing includes depositing a first braze material to a first joint location between a first component having a first coefficient of thermal expansion and an intermediate component. The first component is fitted to the intermediate component at room temperature at the first joint location. A second braze material is deposited to a second joint location between the intermediate component and a second component having a second coefficient of thermal expansion. The second component is fitted to the intermediate component at room temperature at the second joint location. The intermediate component has a coefficient of thermal expansion between the first coefficient of thermal expansion and the second coefficient of thermal expansion.