Sacrificial Yarn Filaments for Uniform CMC Matrix Infiltration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ceramic matrix composites (CMCs) exhibit significant porosity, particularly in the center, which affects in-plane and inter-laminar properties and oxidation resistance, due to non-uniform distribution of matrix material during fabrication processes like CVI, PIP, and MI.
Innovation Solution
Incorporating sacrificial yarn filaments with ceramic filaments in the composite tow, which decompose, dissolve, or melt at elevated temperatures, creating spaces for uniform matrix infiltration, thereby reducing void formation and enhancing matrix distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional preform fabrication methods are used, then the CMC structure can be formed, but significant porosity develops particularly in the center of the structure
Solution Approach 1:
Sacrificial yarn filaments are incorporated into the composite tow before the infiltration process. These filaments are positioned in advance to occupy space that will later be filled by matrix precursor, ensuring uniform distribution of matrix material throughout the final composite structure, particularly in the center region.
Solution Approach 2:
The sacrificial yarn filaments act as intermediary elements during the infiltration process. They temporarily occupy space within the tow, facilitating uniform precursor penetration, and are subsequently removed to create voids that are filled by matrix material, achieving uniform matrix distribution.
2Volume of moving object
If preform thickness is increased, then the CMC structure can accommodate larger components, but porosity significantly increases
Solution Approach 1:
For thicker preforms, sacrificial yarn filaments are incorporated in advance to ensure that matrix precursor can penetrate uniformly throughout the entire thickness. The filaments are distributed throughout the volume to create pathways and spaces that facilitate deep infiltration, preventing center porosity even in thick sections.
3Manufacturing precision
If sacrificial yarn filaments are incorporated in the composite tow, then uniform matrix distribution is achieved, but the device complexity increases
Solution Approach 1:
The sacrificial yarn filaments are distributed uniformly throughout the composite tow, creating a homogeneous structure before infiltration. This uniform distribution ensures that matrix precursor penetrates evenly throughout the preform, achieving homogeneous matrix distribution in the final composite.
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 method results in a more uniform ceramic matrix composite with reduced voids and improved mechanical properties by ensuring even matrix distribution throughout the composite.
Implementation Method 1
the sacrificial yarn filaments are operative to undergo decomposition, dissolution or melting upon being subjected to an elevated temperature
Implementation Method 2
the sacrificial yarn filaments are operative to undergo decomposition, dissolution or melting upon being subjected to an elevated temperature
Implementation Method 3
the sacrificial yarn filaments are operative to undergo decomposition, dissolution or melting upon being subjected to an elevated temperature
Implementation Method 4
The chemical vapor infiltration (CVI) process is commonly used to dispose matrix material into fibrous preforms by the use of reactive gases at elevated temperature to form fiber-reinforced composites
Implementation Method 5
the sacrificial yarn filaments leave open spaces in the tow upon being subjected to decomposition, dissolution or melting
Data Source
AI summary
Disclosed herein is a composite tow comprising a plurality of ceramic filaments; one or more sacrificial yarn filaments; where the sacrificial yarn filaments are operative to undergo decomposition or melting upon being subjected to an elevated temperature; and wherein the sacrificial yarn filaments leave open spaces in the tow upon being subjected to decomposition, dissolution or melting; where the filaments have an average filament diameter of 5 to 15 micrometers.