Crack Paths 2009

reduce drastically to be almost constant after 800 hrs of hydrogen charging. In the

second stage, the HIC growth in both series of plates was by the interconnection of

cracks. It is important to point out that, independently of the number of nucleated cracks

(which was much higher in Plate B than in plate A), the final cracked area for both

plates was almost the same after 800 hrs; this result may indicate that the HIC kinetics

is controlled by the growth process and not by the nucleation.

2days

4days

8days

15 days

27 days

35 days

Figure 3. Crack contours by ultrasonic mapping of Plate B.

1200

)

246800

(m m

g a r e a

a c k in

1000 C r

Plate B

Plate A

200

800

0

400

600

1000

Exposure time (hr)

Figure 4. Crack growth rate for Plates A and B.

805