Breakthrough Materials for Aero Engine Applications?

47 Pages·2012·5.04 MB·English

High-Entropy Alloys
Breakthrough Materials for Aero Engine Applications?
By Daniel Svensson, Gothenburg, 13/2 2015
Presentation Outline
1. Introduction
2. High-Entropy Alloys
3. Aero Engine Materials
4. Bridging the Gap
5. Suggested Systems
6. Summary
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Introduction
● GKN Aerospace Engine Systems in
Trollhättan manufactures engine
parts
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● Current superalloys (ρ> 8 g/cm )
● High-entropy alloys are potential
candidate materials
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Introduction
● High-entropy alloys is a new type of metallic
materials
● Exciting properties
○ Good strength
○ Retain strength at elevated temperatures
4
Introduction
● Review high-entropy alloys
● Review state-of-the-art aero
engine materials
● Identify problems left to solve
● Suggest potential high-
entropy alloy systems
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Presentation Outline
1. Introduction
2. High-Entropy Alloys
3. Aero Engine Materials
4. Bridging the Gap
5. Suggested Systems
6. Summary
6
High-Entropy Alloys
1. Definition
2. Four core effects
3. Typical properties
4. Processing routes
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Definition
● Conventional (low- and medium-entropy) alloys
○ 1-3 principal components with 1 or more minor
components
Steels, aluminium alloys...
● High-entropy alloys
○ 5-13 principal components
○ (Not the only definition, they can also be defined
according to their configurational entropy)
AlCoCrFeNi, AlMo NbTa TiZr...
0.5 0.5
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Four Core Effects
1. High mixing entropy effect
○ Gibbs free energy
○ High configurational entropy can suppress ordered phases
○ Especially at higher temperatures
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[High-Entropy Alloys - Murty B.S., Yeh J.W., Ranganathan S.]
Four Core Effects
[Sluggish diffusion in Co–Cr–Fe–Mn–Ni high-
entropy alloys]
2. Sluggish diffusion effect
○ Fluctuating potential energy
due to many different
elements
○ Much coordination of
elements needed
Good elevated temperature properties
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