Porous Metal Repair Coupon With Sealed Cavity for Braze Infiltration
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Solution Overview
Problem
Existing component repair methods using additively manufactured coupons suffer from limitations such as material costs, performance characteristics, and joint reliability, as the replacement coupons are made with the same materials and structure as the original component.
Innovation Solution
A metal coupon system comprising additively manufactured metal parts with a sealed cavity and a porous region around it, allowing for variable porosity and customized braze material infiltration to improve performance characteristics and reduce material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If replacement coupons are made with the same materials and structure as the original component, then the coupon shape matches the cutout and basic structural integrity is maintained, but material costs increase and performance characteristics such as joint adhesive bond strength and stress/strain resistance do not improve
Solution Approach 1:
The coupon uses a composite structure combining a porous metal substrate with braze material infiltrated into the pores. This composite construction provides improved joint adhesive bond strength and stress/strain resistance while using less expensive material combinations, directly resolving the contradiction between reliability improvement and material cost reduction
Solution Approach 2:
The coupon features a porous region with controlled porosity (30-70%) in specific areas rather than uniform structure throughout. This local variation in material density allows optimized braze material infiltration where needed, improving joint strength at the bonding interface while maintaining cost efficiency in other regions
2Reliability
If a single braze material is used to couple the replacement coupon to the component, then the brazing process is simple, but joint adhesive bond strength and reliability cannot be optimized and required post-braze machining/blending increases
Solution Approach 1:
The porous region provides localized control over braze material infiltration, allowing the braze material to concentrate precisely where needed at the bonding interface. This eliminates the need for post-braze machining or blending to achieve proper joint geometry, as the porous structure self-regulates the braze material distribution
Solution Approach 2:
The porous metal substrate acts as a capillary network that automatically draws and distributes braze material during the brazing process. This porous structure ensures complete and uniform braze material infiltration throughout the coupon interface, improving joint reliability while eliminating the need for additional machining steps
3Strength
If replacement coupons use the same material as the original component, then material compatibility is maintained, but the ability to improve general performance characteristics such as strength, stress/strain resistance, ductility, wear resistance, thermal or electrical conductivity is prevented
Solution Approach 1:
The coupon employs a composite material system where the porous metal substrate provides structural framework and the infiltrated braze material provides enhanced mechanical properties. This composite approach enables superior stress/strain resistance and other performance characteristics that cannot be achieved with a single material, directly enabling performance improvement while maintaining material compatibility through careful selection of compatible metal and braze material combinations
Solution Approach 2:
The additive manufacturing process enables precise control over the porous structure parameters including porosity (30-70%), pore size distribution, and pore connectivity. By varying these parameters, the coupon can be optimized for different performance requirements such as strength, thermal conductivity, or weight reduction, providing versatility in performance characteristic improvement
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 metal coupon system enhances performance characteristics such as joint adhesive bond strength, stress/strain resistance, and reduces material costs by allowing customized braze material distribution and improved structural integrity.
Implementation Method 1
a porous region around the sealed cavity... configured to accept braze material therein
Data Source
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AI summary
A metal coupon (200) for repairing a component (202) includes an additively manufactured (AM) metal member (330) having a sealed cavity (296) in an interior of the AM metal member (330), and a porous region (300) around the sealed cavity (296). A metal coupon system (210) may include at least two AM metal parts (292) with each AM metal part (292) including at least a section (294) of a sealed cavity (296) therein and a porous region (300) around the at least a section (294) of the sealed cavity (296). The AM metal parts (292) combine to form the metal coupon (200), i.e., AM metal member (330), with the sealed cavity (296) in an interior thereof and the porous region (300) around the sealed cavity (296). In any event, the sealed cavity (296) is hollow. The porous metal coupon (300) with sealed cavity (296) provides reduced mass and allows braze material (310) to be directed based on characteristics of the porous region (300).