Composite components and methods for preventing flow from infiltrated component during re-infiltration
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Solution Overview
Problem
During the infiltration of green, uninfiltrated material into a previously infiltrated ceramic matrix composite (CMC) component, constituents such as silicon can migrate from the original CMC component to the green material, weakening the resulting composite.
Innovation Solution
Incorporating a barrier segment with lower permeability than the infiltrated and green segments to prevent the migration of constituents by creating a drop in permeability at the interface, ensuring flow originates from an external source during infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If green, uninfiltrated material is laid up with the original CMC component and subjected to infiltration, then porosity is reduced and the green material is strengthened, but free silicon or other constituents in the original CMC component migrate from the original component to the green material, weakening the original CMC component portion
Solution Approach 1:
The CMC component is divided into distinct segments: the original infiltrated segment, the green segment, and a barrier segment positioned between them. This segmentation prevents direct contact and material migration between the infiltrated and green segments during subsequent infiltration processes.
Solution Approach 2:
A barrier segment is introduced as an intermediary between the infiltrated segment and the green segment. This barrier segment has lower permeability and acts as a mediator that prevents free silicon or other constituents from migrating from the infiltrated segment to the green segment during infiltration.
2Reliability
If a barrier segment with lower permeability is positioned between the infiltrated segment and the green segment, then migration of constituents is prevented, but the device complexity increases
Solution Approach 1:
The barrier segment is positioned locally at the interface between the infiltrated and green segments where material migration is most likely to occur. This localized approach provides the necessary protection without requiring the entire component to be redesigned, thereby limiting the increase in complexity.
Solution Approach 2:
The barrier segment is formed from composite material with specifically engineered lower permeability properties. This allows the barrier to be integrated into the existing composite component structure using compatible materials and manufacturing processes, reducing the impact on overall device complexity.
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
Prevents the formation of voids, cracks, and other undesirable elements by arresting the flow of constituents from the infiltrated segment to the green segment, maintaining the integrity of the composite component.
Implementation Method 1
the barrier segment has a lower permeability, e.g., through a different microstructure, than one or both of the infiltrated segment and the green segment to slow or prevent migration or redistribution of material
Data Source
AI summary
A method for modifying a composite component may include positioning a barrier segment between an infiltrated segment of the composite component and a green segment to form an assembly; and initiating an infiltration process. The barrier segment may have a barrier segment permeability that is lower than a permeability of the infiltrated segment, a permeability of the green segment, or both. A composite component may include an infiltrated segment infiltrated with a molten material during a prior infiltration process; a green segment that is uninfiltrated; and a barrier segment having a microstructure different from the infiltrated segment, the green segment, or both. The microstructure of the barrier segment may be configured to slow a flow of material between the infiltrated segment and the green segment during a subsequent infiltration process.