Fractography Resource - 1 Examples of Fractography in Other Materials Professor M Neil James Department of Mechanical & Marine Engineering University of Plymouth Drake Circus, Plymouth PL4 8AA ENGLAND

Fractography Resource - 2 Contents – Use the hyperlinks to navigate around this resource  WC-Co : Compression and tensile fatigue WC-Co : Compression and tensile fatigue  316L stainless steel – SCC 316L stainless steel – SCC  Fatigue in polycarbonate Fatigue in polycarbonate  Fast fracture in polycarbonate Fast fracture in polycarbonate

Fractography Resource - 3 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

Fractography Resource - 4 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

Fractography Resource - 5 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 Back to Contents

Fractography Resource L 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 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

Fractography Resource L 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 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

Fractography Resource L 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 mm thick, 120 mm diameter seam welded pipe used to transport glucose solution Fracture surface shows brittle appearance – not fatigue crack growth

Fractography Resource L 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 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

Fractography Resource L 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 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 10 4 ppm of chlorides present Back to Contents

Fractography Resource - 11 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

Fractography Resource - 12 Fatigue in polycarbonate  YS = 20 MPa (initial cyclic yield) - annealed state – 2 mm thick plate R = 0.5 Near the notch root

Fractography Resource - 13 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

Fractography Resource - 14 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

Fractography Resource - 15 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

Fractography Resource - 16 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 Back to Contents