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·
The
diagram illustrates the dependence of the Fracture Toughness, K1C,
of a material on the time of immersion in a corrosive electrolyte. The
sample is placed under uniaxial tension, and pre-cracks have been initiated
at the tips of the stress concentrating notches in the central hole.
·
The
fracture toughness is plotted against immersion time, and is seen to decrease
to a long term limit, K1scc,
the stress corrosion cracking value. This value is significantly below
the fracture toughness measured in an inert environment and below the yield
strength of the sample.
· For
a steel sample tested in sea water, the fracture toughness decrease may
be 40%. This restricts the flaw size for ,a href="../glos324/plasticdeformation.htm">plastic deformation failure rather
than rapid crack propagation. |
