CMC Repair via Localized Thermal Gradient Control
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Solution Overview
Problem
Current methods for repairing ceramic matrix composite (CMC) components in gas turbine engines face challenges such as matrix material liquification and stress crack formation due to uneven heating, which can lead to inefficiencies and damage during the repair process.
Innovation Solution
A method involving positioning repair material within a repair region of a composite component, heating the repair region to a temperature at or above the melting point of the infiltrant, and heating the remaining portion to a lower temperature to prevent liquification and stress cracks, while using a system with heating elements and a vacuum chamber to control thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the entire CMC component is heated to the melting temperature of its matrix material, then the new CMC material can fuse with the existing CMC material, but the matrix material of portions not being repaired may liquify and flow out of the component
Solution Approach 1:
The patent applies local quality by heating only the repair region to the melting temperature of the matrix material, while maintaining the remaining portion at a lower temperature. This localized thermal treatment allows the new CMC material to fuse with existing material at the repair site without causing the matrix material in other regions to liquify and flow out, thus resolving the technical contradiction between achieving strong fusion and preventing harmful material loss.
2Ease of manufacture
If only the portion of the CMC component adjacent to the new CMC material is heated to the melting point of the matrix material, then the repair region can be treated, but stress cracks may form within the component
Solution Approach 1:
The patent applies parameter changes by carefully controlling the temperature distribution across different regions of the CMC component. The repair region is heated to the melting point of the matrix material to enable fusion, while the remaining portion is maintained at a lower temperature to prevent stress crack formation. This graduated temperature parameter control resolves the contradiction between localized heating efficiency and prevention of thermal stress damage.
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 allows for effective fusion of new composite material with existing material without liquification or stress cracks, ensuring a robust and efficient repair process for CMC components.
Implementation Method 1
heating the repair region to a first temperature... the first temperature is at or above a melting point of the infiltrant
Implementation Method 2
melt infiltrating the repair region with an infiltrant to densify the repair material
Data Source
AI summary
A method for repairing composite components includes positioning repair material within a repair region of a composite component formed of a composite material. Furthermore, the method includes heating the repair region to a first temperature. Additionally, the method includes heating a remaining portion of the composite component to a second temperature. Moreover, the method includes melt infiltrating the repair region with an infiltrant to densify the repair material. The first temperature is at or above a melting point of the infiltrant and the second temperature is less than the melting point.