AM Porous Metal Joint Structure for Repaired Component Interfaces
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Solution Overview
Problem
Existing methods for repairing industrial components, such as turbomachine nozzles, using additively manufactured porous regions do not improve the performance characteristics of the replaced sections, and they require additional materials and processes that increase costs and complexity.
Innovation Solution
The use of an additively manufactured metal porous region with a porosity between 2% to 50% between a dense base region and a dense replacement region, coupled with a braze material that infiltrates the porous region based on its porosity characteristics, to enhance the structural and performance properties of the repaired component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If replacement porous regions are made with the same materials and exterior structure as the removed portion, then the replacement regions can be manufactured, but the performance characteristics such as strength, oxidation resistance, and joint reliability are not improved
Solution Approach 1:
The patent applies porous materials by creating a replacement region with controlled porosity (2%-50% open space volume) that is additively manufactured with a porous structure. This porous structure allows braze material to infiltrate during the brazing process, creating a mechanically interlocked joint that significantly improves joint reliability and strength compared to traditional solid-to-solid brazing. The porous structure acts as a mechanical anchor for the braze material, preventing joint failure.
Solution Approach 2:
The patent creates a composite structure consisting of three distinct regions: the dense base region, the porous replacement region with intermediate properties, and the dense replacement portion. This composite approach allows each region to be optimized for its specific function - the porous region serves as both a structural element and a braze material reservoir, while the dense regions provide structural integrity. The braze material infiltrated into the porous region creates a composite joint structure that enhances overall reliability.
2Strength
If a single braze material is used to couple the replacement porous region to the component, then the coupling process is simplified, but the joint adhesive bond strength and reliability cannot be maximized
Solution Approach 1:
The patent changes the physical parameters of the replacement region by introducing controlled porosity (2%-50% open space volume) rather than using a solid structure. This parameter change fundamentally alters how the braze material interacts with the replacement region during brazing. The porous structure increases the surface area and volume available for braze material infiltration, creating a larger bonding interface and significantly enhancing joint adhesive bond strength without complicating the brazing process itself.
Solution Approach 2:
The porous structure of the replacement region serves as a reservoir and conduit for the braze material during the brazing process. The interconnected pores allow the molten braze material to infiltrate deeply into the replacement region, creating a mechanically interlocked joint. This porous material approach maximizes the bonding interface area and creates a gradient structure that enhances joint strength and reliability.
3Quantity of substance
If porous regions are made with the same material as the removed cutouts, then manufacturing is straightforward, but material costs are not reduced and stresses at joints may increase
Solution Approach 1:
The patent applies local quality by creating a replacement region with spatially varying porosity - the porous structure is localized to specific areas where it provides maximum benefit for braze material infiltration and stress distribution. The porosity can be varied within the replacement region to optimize both mechanical properties and material cost. This localized porous structure allows use of cost-effective materials while maintaining joint strength through the braze infiltration mechanism.
Solution Approach 2:
The patent changes the structural parameters of the replacement region by introducing controlled porosity (2%-50% open space volume) rather than using solid material. This parameter change reduces the amount of expensive high-performance material needed while maintaining or improving joint strength through the braze infiltration mechanism. The porous structure also reduces stress concentration at joints by distributing loads more evenly throughout the replacement region.
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 strengthens the joint between the base and replacement regions, improves performance characteristics such as strength, oxidation resistance, and thermal conductivity, while reducing material costs and eliminating the need for post-braze machining.
Implementation Method 1
a braze material coupling the dense first region, the AM porous region and the dense second region together, the braze material infiltrated into the AM porous region based at least on a characteristic of the porosity
Data Source
AI summary
A component includes a dense base region, a dense replacement region and an additively manufactured (AM) porous region between the dense base region and the dense replacement region. The porous region has a porosity between 2% to 50% open space volume to total volume of the AM porous region. The porous region can be printed onto the base region or the replacement region. A braze material couples the base region, the porous region and the replacement region together, and infiltrates into the porous region based at least on a characteristic of the porosity. The porous region reduces stress at a joint between the dense regions and can be customized to create different physical characteristic(s) than just those of the base and replacement regions.