抄録
The elastic-plastic fracture toughness, JIc, and the stable crack growth characteristics of an aluminum alloy, 5038-O, were evaluated using center cracked tension specimens. To investigate growth and coalescence of voids, a fractographic approach was attempted. The results obtained are as follows:
(1) The critical stretched zone width, SZWc, becomes constant regardless of the specimen thickness, B, and the initial crack length, a0, and it agrees with the SZWc obtained using compact (CT) specimens. So, the JIc value determined using a subcritical stretched zone width, SZW, versus J blunting line is identical to the JIc of CT specimens.
(2) The relation between the net section stress, σnet, and the crack extension, Δa, is not influenced by B nor by a0.
(3) Regardless of the macroscopic fracture modes (the flat fracture or the slant fracture), the stable crack growth preceeds in the midthickness of the specimen.
