Ceramic-Metallic Composite Heat Shield for Gas Turbines
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Solution Overview
Problem
Current ceramic heat shields in gas turbines are prone to cracking and breaking due to thermal shock and acoustic vibrations, leading to significant damage to turbine blades and vanes, and attempts to reinforce them with metallic scaffolds have been unsuccessful due to mismatched thermal expansion coefficients.
Innovation Solution
A composite material comprising a metallic lattice and ceramic matrix, where the metallic lattice pervades the ceramic matrix, manufactured using additive manufacturing techniques such as selective laser melting or electron beam melting, to provide mechanical reinforcement and match thermal expansion coefficients, preventing delamination and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic heat shields are used in gas turbines, then they can withstand high temperatures, but they are prone to cracking and breaking due to thermal shock and acoustic vibrations
Solution Approach 1:
The patent applies composite materials by combining ceramic matrix with metallic reinforcement phases to create a heat shield that maintains high temperature resistance while gaining improved mechanical strength and crack resistance. The composite structure allows the material to withstand thermal shock and acoustic vibrations better than pure ceramic.
Solution Approach 2:
The patent changes the material parameters by introducing metallic phases (such as nickel-based superalloys) into the ceramic matrix, thereby modifying the thermal and mechanical properties. This parameter change enables the heat shield to maintain integrity under thermal shock and vibrational loads while withstanding high temperatures.
2Strength
If ceramic heat shields are reinforced with metallic scaffolds, then mechanical strength is improved, but delamination occurs due to mismatched thermal expansion coefficients
Solution Approach 1:
The patent carefully selects metallic reinforcement phases whose thermal expansion coefficients are matched to the ceramic matrix. This parameter matching prevents delamination while providing mechanical reinforcement. The metallic phases are chosen specifically to have compatible thermal expansion properties with the ceramic material.
Solution Approach 2:
The patent creates a composite material system where ceramic and metallic phases are combined in a way that their complementary properties are utilized. The ceramic provides high temperature resistance while the matched metallic phases provide mechanical strength without causing delamination due to thermal expansion mismatch.
3Ease of manufacture
If additive manufacturing is used to manufacture heat shields, then manufacturing complexity is reduced and customization is enabled, but the material must withstand extreme thermal and mechanical loads
Solution Approach 1:
The patent employs composite materials that can be manufactured via additive manufacturing processes. The composite structure with ceramic matrix and metallic reinforcement phases is designed to be built layer-by-layer, enabling complex geometries and customized cooling channels while maintaining the mechanical strength and thermal resistance required for turbine applications.
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 composite material effectively withstands thermal and mechanical loads up to 1500°C, preventing the ceramic from breaking or peeling off, thus reducing secondary damage to the turbine components.
Implementation Method 1
the metallic lattice pervades the ceramic metrics, thereby mechanically reinforcing or supporting the ceramic matrix against thermal and/or mechanical loads or impacts
Implementation Method 2
additively manufacturing the metallic lattice, e.g. by powder bed based selective laser melting or electron beam melting
Implementation Method 3
sintering the infiltrated metallic lattice, wherein the ceramic powder is solidified and the composite material is formed
Implementation Method 4
attempts to reinforce a heat shield, such as a CHS with a metallic scaffold, in order to overcome the described drawbacks of delamination, failed. This may be due to the difficulty of adapting thermal expansion coefficients of the dissimilar materials involved
Data Source
Figure 1~2
Figure 3~4
AI summary
A Composite material (10) for an application in a turbo machine (100) is presented. The composite material (10) comprises a metallic lattice (1) and a ceramic matrix (2), wherein the metallic lattice (1) pervades the ceramic matrix (2), thereby mechanically reinforcing the ceramic matrix (2) against thermal and/or mechanical loads in an application of the composite material (10).