Fractography
A comparative study was entitled on the fracture surfaces of as-received material with baked material (45 min). About
1.5 cm of longitudinal as-received sample with a fracture surface was taken for fractographic analysis under the SEM. This
showed a fibrous appearance with secondary cracks (see Fig. 3a) at a magnification of 20 mm [5]. However, a detailed looked
at higher magnification (see Fig. 3b) revealed brittle fracture with some dimple appearance, which clearly conforms the
hydrogen attack of some form or other.
To diminish the effect of hydrogen, the sample was then baked at a temperature of 200 8C for 45 min and was then broken
by tensile overload. Sample failed in a typical shape as seen in Fig. 3c and d. Both longitudinal and transverse fracture
surfaces were visible in the sample.
The fracture surface revealed the fibrous ductile fracture morphology on the longitudinal cracked surface. Dimple
appearances on the both transverse and longitudinal fracture surfaces were also seen (see Fig. 3e). A closer view of the
transverse fracture surface (Fig. 3f) shows a dimpled appearance.