This paper examines both fatigue life and crack growth rate behavior of smooth as well as mechanically scratched (of predetermined depth) 2024-T3 aluminum alloy. The presence of scratch in general reduces life; life is seen to reduce continuously with increasing scratch depth. The life behavior, as it is shown here, are in line with the crack growth rate data obtained in scratched specimens. The crack growth rate data are similar to th behavior exhibited usually by short fatigue cracks; they are higher particularly at low stress intensities in compared to conventional long (elastic) crack and scratch depth simply increases this disparity. An additional attempt has also been made to test the life data against an earlier work of one of us (PKM, Ref. 3) that focuses crack initiation life from the point of view of microcrack interactions. The scratched specimens seem to owe the virtues to their increased tendency for cracking.
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