Microstructure Studies of Microstructure Studies of Carbon-Carbon Composite Carbon-Carbon Composite

MaterialsMaterials

Kei YamamotoKei Yamamoto

Purdue UniversityPurdue University

Advisor: Prof. Alex KingAdvisor: Prof. Alex King

Presentation OutlinePresentation Outline

Background information on Carbon-Background information on Carbon-Carbon CompositesCarbon Composites

Optical Microscopy imagesOptical Microscopy images X-ray diffraction resultsX-ray diffraction results SEM imagesSEM images ConclusionsConclusions Future WorkFuture Work

What are Carbon-Carbon Composites?What are Carbon-Carbon Composites?

Amorphous carbon Amorphous carbon matrix compositematrix composite

Carbon matrix Carbon matrix reinforced by graphitic reinforced by graphitic carbon fiberscarbon fibers

First developed in First developed in 1958, but not 1958, but not intensively researched intensively researched until the Space Shuttle until the Space Shuttle Program (for Program (for insulation)insulation)

How are Carbon-Carbon How are Carbon-Carbon composites made?composites made?

First carbon fibers are made by pyrolizing Poly-acrylo-First carbon fibers are made by pyrolizing Poly-acrylo-nitrile (PAN) fibers nitrile (PAN) fibers

Pyrolized fibers then woven into the desired patternPyrolized fibers then woven into the desired pattern

Spaces between the fibers are filled by Chemical Spaces between the fibers are filled by Chemical Vapor Deposition (CVD)Vapor Deposition (CVD)

http://www.fibermaterialsinc.com/frSW.htm

Properties of Carbon-Carbon Properties of Carbon-Carbon CompositesComposites

Outstanding durability at temperatures over Outstanding durability at temperatures over 2000ºC2000ºC

Low coefficient of thermal expansionLow coefficient of thermal expansion Great thermal shock resistanceGreat thermal shock resistance High strength High strength Low weightLow weight High melting pointHigh melting point Corrosion resistantCorrosion resistant ExpensiveExpensive Long time to manufacture (weeks to months)Long time to manufacture (weeks to months)

Properties of Carbon-Carbon Properties of Carbon-Carbon

http://www.hitco.com/products/corrosion/chemical/index.html

http://www.hitco.com/products/corrosion/chemical/index.html

Uses of Uses of Carbon-CarbonCarbon-Carbon CompositesComposites

Aircraft, F-1 racing Aircraft, F-1 racing cars and train cars and train brakesbrakes

Space shuttle nose Space shuttle nose tip and leading tip and leading edgesedges

Rocket nozzles and Rocket nozzles and tipstips

http://www.futureshuttle.com/conference/ThermalProtectionSystem/Curry_73099.pdf

http://www.fibermaterialsinc.com/frSW.htm

http://www.fibermaterialsinc.com/frSW.htm

Original goals of my projectOriginal goals of my project

To determine how the microstructure of the To determine how the microstructure of the carbon-carbon composites affect the carbon-carbon composites affect the properties of aircraft brakesproperties of aircraft brakes

To find out the best methods to determine To find out the best methods to determine porosity and fiber alignment to be used as porosity and fiber alignment to be used as quality control testsquality control tests

Sample 1Sample 1

Sample 2Sample 2

Sample 3Sample 3

Sample 4Sample 4

Optical MicroscopyOptical MicroscopySample 1:

Optical MicroscopyOptical MicroscopySampleSample 22::

Optical MicroscopyOptical MicroscopySample 3:Sample 3:

X-ray Diffraction Results X-ray Diffraction Results

Sample1

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X-ray Diffraction ResultsX-ray Diffraction Results

Sample2

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X-ray Diffraction ResultsX-ray Diffraction Results

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X-ray Diffraction ResultsX-ray Diffraction Results

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MicrotomeMicrotome Cuts thin slices (microns Cuts thin slices (microns

thick) of your specimen thick) of your specimen Specimen must be soft Specimen must be soft

Beem Capsule Microtome

Microtomy ResultMicrotomy Result

Sample #Sample # Mass Mass Before Before HeatingHeating

Mass After Mass After HeatingHeating

% Mass % Mass ChangeChange

11 2.03582g2.03582g 2.035472.03547 0.01719%0.01719%

22 1.78192g1.78192g 1.78138g1.78138g 0.0303%0.0303%

33 1.16317g1.16317g 1.13793g1.13793g 2.1699%2.1699%

44 2.74388g2.74388g 2.72870g2.72870g 0.55323%0.55323%

SEM ImagesSEM Images

Sample 1:Sample 1:

SEM ImagesSEM Images

Sample 2:Sample 2:

SEM ImagesSEM ImagesSample 3:Sample 3:

SEM ImagesSEM ImagesSample 4:Sample 4:

ConclusionsConclusions

Crystallinity of carbon fibers varies considerably Crystallinity of carbon fibers varies considerably between specimensbetween specimens

In samples 2, 3 and 4 the amorphous carbon matrix In samples 2, 3 and 4 the amorphous carbon matrix and carbon fibers are not well bound together, thus and carbon fibers are not well bound together, thus matrix is not providing any benefits to the structurematrix is not providing any benefits to the structure

In sample 1 amorphous carbon matrix and carbon In sample 1 amorphous carbon matrix and carbon fibers are bound together but it is not inter-grown fibers are bound together but it is not inter-grown together, thus matrix is still not providing any together, thus matrix is still not providing any benefits to the structurebenefits to the structure

Carbon was only deposited on the surface in one of Carbon was only deposited on the surface in one of the specimens: amorphous carbon nucleation is the specimens: amorphous carbon nucleation is found only very rarely on the fiber surfaces in this found only very rarely on the fiber surfaces in this specimenspecimen

Future WorkFuture Work

Improvement of the sectioning process to Improvement of the sectioning process to retain shell and core structure of carbon-retain shell and core structure of carbon-carbon composite carbon composite

Refine techniques for embedding the material Refine techniques for embedding the material Develop a capacity for thin section specimens Develop a capacity for thin section specimens

for transmitted light microscopy and TEMfor transmitted light microscopy and TEM Routine SEM and XRDRoutine SEM and XRD Relate results to processing the samples Relate results to processing the samples

have been exposed tohave been exposed to

AcknowledgementsAcknowledgements

Prof. Alex King Prof. Alex King Indiana 21Indiana 21stst Century fund Century fund HoneywellHoneywell

Questions?Questions?