CMC Pre-form Mold from Scrap for Infiltration
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Solution Overview
Problem
The processing of ceramic matrix composite (CMC) components for gas turbines faces challenges such as incomplete densification, porosity, and microstructural defects due to difficulties in matrix infiltration, especially in thick sections with high fiber volume fractions and non-uniform fiber distributions, leading to mechanical property degradation.
Innovation Solution
A method involving the use of a pre-form CMC mold formed from randomly arranged CMC remnant scrap material, debulked into a rigidized shape with controlled gaps, which is then used in a lay-up process with autoclaving to densify the CMC plies, improving infiltration and reducing premature interlaminar failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If melt infiltration is used to process thick CMC sections with high fiber volume fractions, then complete densification is achieved, but processing time must be extended which damages the fiber-matrix interface
Solution Approach 1:
The patent creates a pre-form mold with an optimized porous structure before infiltration. The mold is pre-configured with controlled porosity (10-50%) and specific pore size distribution, allowing infiltrant to flow through more efficiently during the infiltration process, achieving complete densification without requiring extended processing times that would damage the fiber-matrix interface
Solution Approach 2:
The invention utilizes a pre-form mold with controlled porosity formed from CMC remnant scrap material. The porous structure is designed with specific characteristics (10-50% porosity, controlled pore size) that facilitate efficient infiltrant flow and distribution throughout the thick section, enabling complete densification while maintaining short processing times
2Loss of substance
If CMC remnant scrap material is used to form molds, then material waste is reduced, but the random arrangement creates unpredictable gap structures
Solution Approach 1:
The patent converts the harmful random arrangement of scrap material into a beneficial feature. The random stacking of CMC remnant pieces creates a natural, distributed porous network that prevents defect concentration in specific areas. This unpredictable gap structure actually improves infiltrant distribution by creating multiple flow paths, turning the manufacturing variability into a performance advantage
Solution Approach 2:
The invention controls the porosity parameter within a specific range (10-50%) rather than requiring uniform gap dimensions. By specifying porosity as a range rather than a precise value, the patent accommodates the natural variability of random scrap arrangement while ensuring sufficient infiltrant flow paths. This parameter approach transforms the precision problem into a controllable quality attribute
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 enhances matrix infiltration, increases load-carrying capability, allows operation at higher temperatures, and improves interlaminar flexibility in thick sections, reducing mechanical property degradation and premature failure.
Implementation Method 1
autoclaving the first base ply, the first set of CMC plies, the pre-form CMC mold, the second set of CMC plies and the second base ply
Data Source
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AI summary
A method of forming a pre-form ceramic matrix composite mold (20) for a ceramic matrix composite (CMC) component (10) including providing pieces of CMC remnant scrap material (30) and randomly arranging the pieces of CMC remnant scrap material (30) relative to one another. The method further includes debulking the pieces of CMC remnant scrap material (30) into a rigidized shape, the rigidized shape having gaps (152) between adjacent pieces of CMC remnant scrap material (30) of about 10 microns and about 10 mm and a gap spacing between about 50 microns and about 50 mm, and forming the rigidized shape into a mold (20).