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The main sections of the museum are listed below;
Metal Fatigue
Manufacturing Faults
Bicycle Components
Corrosion
Polymers
Composite Materials
Tools of the trade, some ways to investigate problems;
Photoelasticity
Dye penetrant testing
Glossary
of materials engineering terms
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Corrosion failures.
Corrosion
A
phenomenon which results from chemical degradation of metals
and alloys due to reaction with agents in the service environment,
e.g. the rusting of steel in moist air. May take the form
of uniform attack over the whole surface or as highly localised
pitting. |
For
further information on the phenomena of corrosion follow this link
to
an explanation of corrosion,
or select links below for stories of specific failures
Click
on pictures below for full size image. |
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The deep drawn
brass cup on the right shows stress corrosion cracking under
the influence of the residual manufacturing stresses and a mildly
corrosive environment. The cup on the left has been annealed
before putting it into service which solves the problem. |
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This is another example
of stress corrosion cracking where residual stress, a susceptible
microstructure and a mildly corrosive atmosphere have caused
rapid cracking in this thick walled brass tube. |
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Many brass plumbing
fittings have electrochemical cells between their constituent
phases. This leads to rapid corrosion cracks which have a coppery
colour due to dezincification where the zinc content is leached
out. |
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The current trend for
aluminium vehicles is not without problems. This aluminium alloy
chassis member shows very advanced corrosion due to contact with
road salt from gritting operations or use in coastal / beach
regions. |
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This bronze
propeller blade appears to have suffered corrosion. However
it is not a chemical attack. Closer examination reveals that
it is associated with the leading edge of the blade.
<Further
information> |
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Failure of aluminium mountain
bike seatpost
<Further
information> |
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This
polished aluminium rim was left over Christmas with road salt
and mud on the rim. Galvanic corrosion has started between
the chromium plated brass spoke nipple and the aluminium rim. |
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Galavanic corrosion
can be even worse underneath the tyre in bicycles used all winter.
Here the corrosion is so advanced it has penetrated the rim thickness.
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