Fig. 89 Crack-initiation locations in compression loading. Crack initiation may occur along the centerline and at the surface on a hoop plane. Further deformation may close the centerline crack. More

Fig. 4 Low magnification SEM micrograph of the crack initiation site, with crack arrest markings noted More

Fig. 1 Crack initiation on type 316LR stainless steel dynamic compression plate. (a) Anterior-posterior radiograph. The plate was used to treat the nonunion of a fracture between the fourth and seventh screws. The plate was bent intraoperatively to fit the contour of the bone. (b) Radiograph More

Fig. 4 Detail crack initiation region in rail 5-1 suggesting merging of two cracks and mechanical damage on fracture surface. (a) 8.5×. (b) 130× More

Fig. 2 Inclusion shape near crack initiation site More

Fig. 9 Crack initiation site A1 and corrosion pits, reinforcement from sea water test. More

Fig. 5 Pin cracks in the fine threaded part, opened up (crack initiation designated by arrows). Pin 5, not cleaned at left, pickled at right. 0.5 × More

Fig. 6 Pin cracks in the fine threaded part, opened up (crack initiation designated by arrows). Pin 3, not cleaned at left, pickled at right, 1 × More

Fig. 7 Coupling cracks, opened up (crack initiation designated by arrows). Coupling 3, not cleaned at left, pickled at right. 1 × More

Fig. 8 Coupling cracks, opened up (crack initiation designated by arrows). Coupling 1, pickled. approx. 0.6 × More

Fig. 4 Fatigue crack initiation and propagation in the turbine blade sample. Arrow ‘O’ indicates initiation region and small arrows depict crack growth direction. (a) Initiation region; (b) Fatigue striations 0.1-mm from crack initiation region; (c) Crack growth bands 1-mm from crack More

Fig. 9 SEM micrograph of cleaned fracture surface, with the crack initiation point at approximately the 1 o'clock position. More

Fig. 3 (a) Shroud plate fracture surface illustrating crack initiation from the defect and subsequent fatigue fracture. (b) Left hand side of the fracture surface shown in Fig. 3(a) sectioned through the defect origin and subsequently cut into three sections to facilitate SEM study. Note More

Fig. 2 Secondary crack initiation at pit-like defect in microstructure that represents an effective quench yet component cracked. More

Fig. 5 Closeup view of the crack initiation area in Fig. 4 . The dark spots are slag inclusions. 11×. More

Fig. 6 Closeup view of fracture surface in Fig. 5 , showing a crack initiation area at a sharp radius between the base metal and the filler meterial.The top half (122×) is an enlarged view of the rectangle in the bottom hen (12×). More

Fig. 9 SEM image of crack initiation region A More

Fig. 2 Macrograph shows fatigue crack initiation site (white) of failed crankshaft LF5. 10× More

Fig. 4 Macrograph shows damaged fatigue crack initiation site of failed crankshaft LF14. 10× More

Fig. 10 SEM micrograph shows LF14 tension-to-tension fatigue crack initiation (FCI) site at planar grain boundary facet (Center). 150× More