Additive Braze Deposition for Low-Stress Component Repair
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Solution Overview
Problem
Existing repair processes for components, such as those in gas turbine engines, face challenges in reducing material waste and minimizing secondary defects, particularly in the formation of defects related to the repair process itself.
Innovation Solution
The method involves using additive manufacturing to deposit braze powder onto a substrate, sintering it with an energy beam, and then subjecting the substrate and sintered braze material to a heat cycle to diffusion bond the braze material, reducing material waste and secondary defects by employing a lower processing temperature compared to traditional welding techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional welding techniques are used to repair components, then strong bonding is achieved, but thermally induced stresses, distortion, and material density issues occur
Solution Approach 1:
The invention changes the processing temperature parameter by using lower melting point braze materials (e.g., nickel-based braze with melting point 1100-1300°C) compared to traditional welding temperatures that melt the substrate. This parameter change allows bonding to occur at reduced temperatures, minimizing thermal stresses and distortion while maintaining strong joints through diffusion bonding mechanisms
Solution Approach 2:
The invention introduces a braze material as an intermediary substance between the substrate and repair material. This braze layer acts as a mediator that bonds to both the substrate and the deposited material, enabling strong bonding without directly melting the substrate and thereby reducing thermally induced stresses and distortion
2Productivity
If additive laser deposition welding is used, then material deposition is achieved, but material waste and secondary defects increase
Solution Approach 1:
The invention changes the energy input parameters by using lower power density and lower processing temperatures compared to laser deposition welding. This allows for more controlled material deposition with reduced vaporization and spatter, thereby minimizing material waste while maintaining deposition efficiency
Solution Approach 2:
The invention converts the typically harmful effect of material vaporization and spatter in laser welding into a benefit by using lower temperatures that prevent excessive vaporization. The reduced thermal energy input prevents material loss while still achieving proper bonding through the braze material's diffusion bonding capability
3Strength
If high temperature processing is used, then complete melting and bonding is achieved, but distortion and secondary defects increase
Solution Approach 1:
The invention changes the temperature parameter from high-temperature welding (melting substrate) to lower-temperature brazing (melting only braze material). This parameter change achieves complete bonding through diffusion bonding at lower temperatures, preventing distortion and secondary defects while ensuring thorough material fusion
Solution Approach 2:
The invention applies local quality by creating a localized heat-affected zone confined to the braze material layer rather than the entire substrate. The braze material locally absorbs and distributes thermal energy, achieving complete bonding at the joint interface while minimizing thermal impact on the surrounding substrate, thereby reducing distortion
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 minimizes thermally induced stresses, distortion, and material density issues associated with additive laser deposition welding, while reducing material consumption and requiring less post-processing, thereby improving the repair efficiency and quality of components like those in gas turbine engines.
Implementation Method 1
The braze powder is sintered to the substrate using an energy beam
Implementation Method 2
The braze powder is sintered together and to the substrate during the depositing of the braze powder
Implementation Method 3
The substrate and the sintered braze material are heated to melt the sintered braze material
Implementation Method 4
diffusion bond the sintered braze material to the substrate
Data Source
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AI summary
A method is disclosed during which a substrate (37) is provided. Braze powder (36) is deposited with the substrate (37) using an additive manufacturing device (22). The braze powder (36) is sintered together and to the substrate (37) during the depositing of the braze powder (36) to provide the substrate (37) with sintered braze material (58). The substrate (37) and the sintered braze material (58) are heated to melt the sintered braze material (58) and diffusion bond the sintered braze material (58) to the substrate (37).