Compliant Metal Layer for CMC-to-Metal Wear Reduction

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Solution Overview

Problem

Ceramic matrix composite (CMC) components experience wear and friction issues when attached to metal components at elevated temperatures, leading to damage and reduced performance in turbine engine applications.

Innovation Solution

A compliant metal layer with a low coefficient of friction is inserted between the CMC and metal components, reducing wear and friction by being compliant relative to the asperities of the CMC surface and maintaining a friction coefficient of 1.0 or less at operating temperatures between 300°C to 325°C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a CMC component is directly attached to a metal component, then the attachment provides structural support and load transfer, but the hard abrasive ceramic material causes wear to the metallic hardware and potential damage to the ceramic surface

Engineering Contradiction:
Improvestructural support and load transferVSAvoidwear to metallic hardware and damage to ceramic surface
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

A metal layer is introduced as an intermediary component between the CMC component and the metal hardware. This intermediate layer serves as a protective barrier that reduces direct contact and friction between the abrasive ceramic surface and the metallic hardware, thereby reducing wear on both surfaces while maintaining the structural support and load transfer functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution employs a composite structure consisting of the CMC component, the intermediate metal layer, and the metal hardware. This multi-material composite approach combines the advantages of each material: the high-temperature strength of CMC, the compliance and wear resistance of the intermediate metal layer, and the structural strength of the metal hardware, thereby resolving the wear contradiction.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If a compliant metal layer is inserted between CMC and metal components, then wear and friction are reduced, but the device complexity increases

Engineering Contradiction:
Improvewear and friction reductionVSAvoidattachment structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The compliant metal layer is applied locally only at the contact surfaces where wear occurs, rather than throughout the entire component. This localized application reduces the overall complexity increase while still providing the wear and friction reduction benefits at the critical interface regions.

Inventive Principle:
Principle #3Local quality

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 solution effectively reduces wear and friction between CMC and metal surfaces, enhancing the durability and performance of CMC-to-metal attachments in high-temperature environments, thereby improving the longevity and efficiency of turbine engine components.

Implementation Method 1

A coefficient of friction between the surface interface of the CMC component and the metal component is about 1.0 or less at an operating temperature between about 300°C to about 325°C

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The surface interface of the metal layer is compliant relative to asperities of the surface interface of the CMC component

Methodology Applied
Scientific EffectCompliance: Elasticity

Data Source

PatentEP2922802B1Apparatus and method to reduce wear and friction between CMC-to-metal attachment and interface
Publication Date: 2024.10.30 GENERAL ELECTRIC TECH GMBH
  • EP2922802B1 patent drawingFigure 1~2
  • EP2922802B1 patent drawingFigure 3~5

AI summary

An apparatus to reduce wear and friction between CMC-to-metal attachment and interface, including a metal layer configured for insertion between a surface interface between a CMC component and a metal component. The surface interface of the metal layer is compliant relative to asperities of the surface interface of the CMC component. A coefficient of friction between the surface interface of the CMC component and the metal component is about 1.0 or less at an operating temperature between about 300°C to about 325°C and a limiting temperature of the metal component.