Fractographic analysis of the overload effect on fatigue crack growth in 2024-T3 and 7075-T6 Al alloys
- 9 Downloads
The effect of single overload on the fatigue crack growth in 2024-T3 and 7075-T6 Al alloys was analyzed. Fatigue tests under constant-amplitude loading with overload peak were carried out on V-notched specimens. Fractographic analysis was used as a principal approach to explain the crack growth retardation due to the overload. Scanning electron microscopy (SEM) analyses were conducted on the fractured surface of failed specimens to study the retardation effect. The obtained results show that the overload application generates a plastic zone in both aluminum alloys. The generated plastic zone is three times larger in the case of 2024-T3 compared to 7075-T6, and thus, a significant crack retardation was induced for 2024-T3. The retardation effect due to the overload for 2024-T3 and 7075-T6 lasted for about 10 mm and 1 mm, respectively, from the point of overload application.
Keywordsfatigue crack growth overload retardation fractography crack tip plasticity
Unable to display preview. Download preview PDF.
The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding the work through the research group (No. RGP-VPP-035).
- B.B. Verma, A. Kumar, and P.K. Ray, Fatigue crack growth delay following overload, Trans. Indian Inst. Met., 53(2000), No. 6, p. 291.Google Scholar
- A.J. McEvily, S. Ishikawa, and C. Makabe, The influence of the baseline R value on the extent of retardation after an overload, [in] Mechanism and Mechanics of Fracture: The John Knott Symposium, Columbus, 2002. p. 37.Google Scholar
- Annual Book of ASTM Standards, Standard A. E647: Standard Test Method for Measurement of Fatigue Crack Growth Rates, ASTM International, 2000, p. 628.Google Scholar
- Y. Murakami, Stress Intensity Factors Handbook, Pergamon Press, Oxford, 1987, p. 9.Google Scholar