Aluminum alloys fatigue behavior

J.F. Major Porosity control and the fatigue behavior in A356—T61 aluminum alloy. AFS Trans. 102, 901-906 (1994)... 

J.C. Newman A review of modeling small-crack behavior and fatigue-life predictions for aluminum alloys. J. Fatigue Fract. Eng. Mat. Struct. 17, 429-439 (1994)... 

The SCC behavior of a high-strength aluminum alloy in several environments is shown in Fig. 7.113. The effect of cyclic stress-intensity range, AK, on the growth of fatigue cracks in the same high-strength aluminum alloy and in similar environments is shown in Fig. 7.125 (Ref 173). The similarity in the shapes of the two sets of curves should be... 

S. Russell, M. Tester, E. Nichols, A. Cleaver, and J. Maynor, Static, Fatigue and Crack Growth Behavior of Friction Stir Welded 7075-T6 and 2024-T3 Aluminum Alloys, Friction Stir Welding and Processing, K.V. Jata, M.W. Mahoney, R.S. Mishra, S.L. Semiatin, and D.P. Field, Ed., TMS, 2001... 

J. C. Ehrstorm, Static and Fatigue Behavior of Spot-Welded 5182-0 Aluminum Alloy Sheet, Weld. J., Vol 78, 1999, p 80s-86s... 

W.W. Sanders, Jr. and F.V. Lawrence, Jr., Fatigue Behavior of Aluminum Alloy Weldments, STP 648, American Society for Testing and Materials, 1978, p 22... 

The fatigue crack propagation for the 3003-0 alloy is compared in Fig. 8 with the behavior of aluminum alloys 2024-T3, 7075-T6, 6061-T6, and 5083-0 The data fall within the response of the other alloys. 

More extensive use of aluminum alloys for service at cryogenic temperatures has resulted in a need for more detailed information about their behavior in both the plain and welded conditions at these temperatures. For example, the moduli, fatigue strengths and those properties related to toughness, such as notch sensitivity and tear resistance, are of prime importance. These properties have been studied at the Alcoa Research Laboratories and a brief review of some of the more important findings follows. 

Figures 6.5 and 6.6 show the so called transition point Nt where elastic and plastic components intersects. Beyond A, it is the elastic component of strain that dominates and control the fatigue life of the material whereas below N, the plastic strain prevails. This actually means that beyond Nt high cycle fatigue becomes the dominant failure mode and the Basquin line may sufficiently well represent the S-N fatigue behavior of the material. Below N instead, low cycle fatigue is the failure mode of the material and Mason-Coffin relationship based on strain amplitude is needed. In the surroundings of N, it is necessary to consider both components. It is worth noting how for the softer steel Man-Ten the transition Nt from plastic to elastic behavior can be placed at about 2 10" cycles while for the harder steel RQC-100 it already happens at about 10 cycles. At 10" cycles the plastic component of strain is only a mere 1/30 of the elastic one. For the aluminum alloy this transition occurs even earlier at about 100 cycles. At about 10 cycles the total curve coincides with the elastic component. The coordinates of Nt can be found by putting Ep = and recalling Eq. (6.10) it yields...

O Connor, B.P.D., Plumtree, A. Fatigue crack propagation behavior and damage accumulation relationships in an aluminum alloy. In Fracture Mechanics 19th Symposium, ASTM STP 969, pp. 787-799 (1988)... 

Ambriz, R.R., Mesmacque, G., Benhamena, A., Ruiz, A., Amrouche, A., Ldpez, V.H. Fatigue crack growth behavior oin 6061-T6 aluminum alloy welds obtained by modified indirect electric ARc technique. Sci. Technol. Weld. Joining 15(6), 514—521 (2010)... 

H. Kroninger and A. Reynolds, R-Curve Behavior of Friction Stir Welds in Aluminum-Lithium Alloy 2195, Fatigue Fract. Eng. Mater. Struct, Vol 25, 2002, p 283-290... 

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