Ceramic Matrix Composite Fiber Concentration Gradient
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Solution Overview
Problem
Ceramic matrix composites (CMCs) exhibit significant porosity, particularly in the center, due to uneven precursor infiltration, leading to density variations and reduced oxidation resistance, which affects their in-plane and inter-laminar properties.
Innovation Solution
A ceramic matrix composite laminate with a gradient in fiber concentration per unit volume from the outermost layer to the interior, where the distance between fibers varies, facilitating uniform precursor infiltration and reducing porosity, achieved by stacking layers with different fiber concentrations and spacings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform fiber concentration is used throughout the preform, then manufacturing is simpler, but porosity increases significantly in the center reducing oxidation resistance
Solution Approach 1:
The patent applies local quality by varying the fiber concentration in different regions of the preform. The outer layers have higher fiber concentration to promote precursor infiltration and form dense, oxidation-resistant matrix, while the center has lower fiber concentration to facilitate precursor access. This spatial variation in fiber concentration locally optimizes each region's properties for its specific functional requirements.
Solution Approach 2:
The patent implements parameter changes by systematically varying the fiber concentration parameter through the thickness of the preform. By controlling the fiber concentration to decrease from outer layers toward the center, the patent creates gradient conditions that fundamentally change the infiltration behavior and final matrix density distribution, resolving the contradiction between manufacturing simplicity and oxidation resistance.
2Strength
If preform thickness is increased to improve structural capacity, then load-bearing capability increases, but porosity increases in the center affecting mechanical properties
Solution Approach 1:
The patent applies local quality by varying the fiber concentration in different regions of the preform. The outer layers have higher fiber concentration to promote precursor infiltration and form dense, oxidation-resistant matrix, while the center has lower fiber concentration to facilitate precursor access. This spatial variation in fiber concentration locally optimizes each region's properties for its specific functional requirements.
Solution Approach 2:
The patent implements parameter changes by systematically varying the fiber concentration parameter through the thickness of the preform. By controlling the fiber concentration to decrease from outer layers toward the center, the patent creates gradient conditions that fundamentally change the infiltration behavior and final matrix density distribution, resolving the contradiction between manufacturing simplicity and oxidation resistance.
3Reliability
If fiber concentration is increased to reduce porosity, then oxidation resistance improves, but precursor infiltration becomes uneven and center regions remain porous
Solution Approach 1:
The patent applies local quality by varying the fiber concentration in different regions of the preform. The outer layers have higher fiber concentration to promote precursor infiltration and form dense, oxidation-resistant matrix, while the center has lower fiber concentration to facilitate precursor access. This spatial variation in fiber concentration locally optimizes each region's properties for its specific functional requirements.
Solution Approach 2:
The patent implements parameter changes by systematically varying the fiber concentration parameter through the thickness of the preform. By controlling the fiber concentration to decrease from outer layers toward the center, the patent creates gradient conditions that fundamentally change the infiltration behavior and final matrix density distribution, resolving the contradiction between manufacturing simplicity and oxidation resistance.
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 results in a more uniform matrix density throughout the composite, enhancing its mechanical properties and oxidation resistance by ensuring complete precursor infiltration and minimizing pore formation.
Implementation Method 1
Within the reaction chamber at an elevated temperature, the preform can be exposed to certain precursors. On being exposed to these precursors at an elevated temperature, a reaction can occur resulting in the deposition of a ceramic on the fibers of the preform to form a ceramic matrix composite.
Implementation Method 2
The porosity can increase with thickness and can significantly impact both the in-plane and inter-laminar properties and overall oxidation resistance of the composite.
Data Source
AI summary
A ceramic matrix composite laminate comprises a ceramic matrix that encapsulates a plurality of layers. Each layer comprises fibers. Each layer comprises a plurality of fill fibers and a plurality of warp fibers or a plurality of bias fibers. The outermost layer contains a different concentration of fibers per unit volume than a layer located near an interior of the ceramic matrix composite laminate. A gradient in the number of fibers exists between the outermost layer and the layer located at the interior of the ceramic matrix composite laminate, or a combination thereof. A combined ceramic matrix composite comprises a plurality of composite laminates; wherein each laminate has a different fiber concentration gradient from another laminate that it is in contact with.