Examples of Fractography in
Other Materials
Professor M Neil James
mjames@plymouth.ac.uk
Department of Mechanical & Marine Engineering
University of Plymouth
Drake Circus, Plymouth PL4 8AA
ENGLAND
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Fractography Resource - mjames@plymouth.ac.uk
Contents – Use the hyperlinks to navigate around this resource

WC-Co : Compression and tensile fatigue

316L stainless steel – SCC

Fatigue in polycarbonate

Fast fracture in polycarbonate
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Fractography Resource - mjames@plymouth.ac.uk
WC-Co : Compression and tensile fatigue
6% Co Grade T6
Rupture = 2190 MPa - average grain size = 1.8 m
The line indicates
the transition
between regions of
compression fatigue
(lower half) and
tensile fatigue
(upper half)
Original
magnification shown
by micron bar
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Fractography Resource - mjames@plymouth.ac.uk
WC-Co : Compression and tensile fatigue
6% Co Grade T6
Rupture = 2190 MPa - average grain size = 1.8 m
Compression fatigue
at higher
magnification – WC
grains are rounded
and Co tear ridges
are less frequent
Original
magnification shown
by micron bar
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Fractography Resource - mjames@plymouth.ac.uk
WC-Co : Compression and tensile fatigue
6% Co Grade T6
Rupture = 2190 MPa - average grain size = 1.8 m
Tensile fatigue at
higher magnification
– WC grains are
more angular and
Co tear ridges are
more evident
Original
magnification shown
by micron bar
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5
Fractography Resource - mjames@plymouth.ac.uk
316L stainless steel - SCC
0.033C 1.44Mn 0.44Si 18.4Cr 8.6Ni 0.016P 0.010S
YS = 205 MPa in annealed state : Vickers hardness 235
2 mm thick, 120 mm
diameter seam
welded pipe used to
transport glucose
solution
Cracking associated
with weld – inner
surface of pipe
shown here –
significant crack
branching
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Fractography Resource - mjames@plymouth.ac.uk
316L stainless steel - SCC
0.033C 1.44Mn 0.44Si 18.4Cr 8.6Ni 0.016P 0.010S
YS = 205 MPa in annealed state : Vickers hardness 235
2 mm thick, 120 mm
diameter seam
welded pipe used to
transport glucose
solution
Cracking associated
with weld – outer
surface of pipe
shown here – less
crack branching
Implication: glucose
is cause of problem,
not external lagging
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Fractography Resource - mjames@plymouth.ac.uk
316L stainless steel - SCC
0.033C 1.44Mn 0.44Si 18.4Cr 8.6Ni 0.016P 0.010S
YS = 205 MPa in annealed state : Vickers hardness 235
2 mm thick, 120 mm
diameter seam
welded pipe used to
transport glucose
solution
Fracture surface
shows brittle
appearance – not
fatigue crack growth
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Fractography Resource - mjames@plymouth.ac.uk
316L stainless steel - SCC
0.033C 1.44Mn 0.44Si 18.4Cr 8.6Ni 0.016P 0.010S
YS = 205 MPa in annealed state : Vickers hardness 235
2 mm thick, 120 mm
diameter seam
welded pipe used to
transport glucose
solution
Have 'feathery'
cleavage facets
present
Implication: SCC,
although detrimental
species not clear
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Fractography Resource - mjames@plymouth.ac.uk
316L stainless steel - SCC
0.033C 1.44Mn 0.44Si 18.4Cr 8.6Ni 0.016P 0.010S
YS = 205 MPa in annealed state : Vickers hardness 235
2 mm thick, 120 mm
diameter seam
welded pipe used to
transport glucose
solution
Pipe operates at
60°C – diagram
indicates that
chloride SCC occurs
at this temperature
in acid solutions with
104 ppm of chlorides
present
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10
Fractography Resource - mjames@plymouth.ac.uk
Fatigue in polycarbonate
YS = 20 MPa (initial cyclic yield) - annealed state – 2 mm thick plate
R = 0.5
Notch root is at the
left of the picture
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Fractography Resource - mjames@plymouth.ac.uk
Fatigue in polycarbonate
YS = 20 MPa (initial cyclic yield) - annealed state – 2 mm thick plate
R = 0.5
Near the notch root
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Fractography Resource - mjames@plymouth.ac.uk
Fatigue in polycarbonate
YS = 20 MPa (initial cyclic yield) - annealed state – 2 mm thick plate
R = 0.5
Near the notch root
The marks are not
fatigue striations
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Fractography Resource - mjames@plymouth.ac.uk
Fatigue in polycarbonate
YS = 20 MPa (initial cyclic yield) - annealed state – 2 mm thick plate
R = 0.5
This position is 7.5
mm from the notch
root
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Fractography Resource - mjames@plymouth.ac.uk
Fatigue in polycarbonate
YS = 20 MPa (initial cyclic yield) - annealed state – 2 mm thick plate
R = 0.5
This position is 17.5
mm from the notch
root
The marks are not
fatigue striations –
they probably relate
to craze size ahead
of the crack tip
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Fractography Resource - mjames@plymouth.ac.uk
Fast fracture in polycarbonate
YS = 20 MPa (initial cyclic yield) - annealed state – 2 mm thick plate
This shows typical
fast fracture in the
PC
Features are very
similar to fatigue
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Fractography Resource - mjames@plymouth.ac.uk