Multi-Braze Powder Deposition for Low-Defect 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, as they often involve braze or weld filler materials that can lead to inefficiencies and defects during the repair process.
Innovation Solution
A method using additive manufacturing that involves depositing and sintering two different braze powders onto a substrate, followed by heating to facilitate diffusion bonding, which reduces material waste and secondary defects by precisely filling voids and forming claddings with minimal thermal stress and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional braze or weld filler materials are used for component repair, then the repair process can be completed, but material waste and secondary defects increase
Solution Approach 1:
The substrate surface is prepared in advance by applying a braze powder coating that creates a receptive layer for subsequent braze material deposition. This preliminary action ensures proper adhesion and reduces defects by pre-conditioning the surface geometry and chemistry before the actual repair operation.
Solution Approach 2:
The process utilizes controlled thermal parameters during the heating stage, where the substrate and braze materials are heated to specific temperature ranges to melt the braze materials and enable diffusion bonding. By precisely controlling temperature, heating rate, and hold time, the process minimizes thermal stress and distortion while achieving reliable repairs with minimal material waste.
2Manufacturing precision
If multiple braze materials are deposited and sintered, then repair precision and material utilization improve, but process complexity increases
Solution Approach 1:
The repair process is segmented into distinct operational stages: substrate preparation with braze powder coating, selective deposition of different braze materials into voids and as cladding, sintering of deposited materials, and final diffusion bonding. Each stage is independently controlled and optimized, allowing precise repair while managing overall process complexity through systematic breakdown of operations.
Solution Approach 2:
The process employs composite braze material systems where different braze alloys (e.g., nickel-based, cobalt-based, or copper-based materials) are selectively deposited in different regions. These composite material applications allow optimization of repair properties in different zones - such as using low-melting-point materials for void filling and high-strength materials for cladding - thereby achieving high repair precision through material heterogeneity.
3Strength
If braze materials are melted and diffusion bonded, then bond strength improves, but thermal stress and distortion increase
Solution Approach 1:
The heating process is applied locally to the repair zone rather than uniformly across the entire substrate. The energy beam (laser or electron beam) concentrates thermal energy only where braze materials need to be melted and bonded, creating a localized heat-affected zone. This localized heating achieves strong diffusion bonding at the repair site while minimizing thermal stress and distortion in the surrounding substrate areas.
Solution Approach 2:
The heating process employs periodic or pulsed energy application rather than continuous heating. By using pulsed laser or electron beam heating with controlled duty cycles, the process allows intermittent heating and cooling periods that reduce cumulative thermal stress while still achieving the necessary temperature for diffusion bonding. This periodic action maintains bond strength while mitigating thermal 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 effectively reduces material waste and secondary defects by using additive manufacturing to deposit and sinter braze powders, resulting in efficient repair processes with reduced thermal stress and distortion, while improving the structural integrity of components like those in gas turbine engines.
Implementation Method 1
The first braze powder is sintered to the substrate during the depositing of the first braze powder to provide the substrate with sintered first braze material. The second braze powder is sintered to the substrate during the depositing of the second braze powder
Implementation Method 2
The sintered first braze material and the sintered second braze material are heated to melt the sintered first braze material and the sintered second braze material
Implementation Method 3
heated to melt the sintered first braze material and the sintered second braze material and to diffusion bond the sintered first braze material and the sintered second braze material to the substrate
Data Source
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AI summary
A method is provided during which first braze powder (40A) is deposited with a substrate (42). The first braze powder (40A) is sintered to the substrate (42) during the depositing of the first braze powder (40A) to provide the substrate (42) with sintered first braze material (62A). Second braze powder (40B) is deposited with the substrate (42). The second braze powder (40B) is different than the first braze powder (40A). The second braze powder (40B) is sintered to the substrate (42) during the depositing of the second braze powder (40B) to provide the substrate (42) with sintered second braze material (62B). The sintered first braze material (62A) and the sintered second braze material (62B) are heated to melt the sintered first braze material (62A) and the sintered second braze material (62B) and to diffusion bond the sintered first braze material (62A) and the sintered second braze material (62B) to the substrate (42).