Effect of strain ratio on cyclic deformation behaviour of 7050-T6 aluminium alloy
Source abstract
Abstract
Abstract This paper aims at investigating the strain ratio effect on cyclic deformation behaviour of 7050-T6 aluminium alloy. Low-cycle fatigue tests are conducted under strain-controlled conditions at three strain ratios (−1, 0, and 0.5) with strain amplitudes in the range 0.60–1.75%. Microstructure is analysed by optical microscopy, transmission electron microscopy and X-ray diffraction, and fracture surfaces are examined by scanning electron microscopy and transmission electron microscopy. The results show that the material exhibits a cyclic strain-softening behaviour whose degree increases with increasing values of strain ratio and decreasing values of strain amplitude. Under non-zero mean strain, full relaxation of mean stress is only observed at higher strain amplitudes. A second order logarithmic model is proposed to account for the mean stress relaxation rates. Lifetime expectancy is reduced as the strain ratio raises which is consistent with the progressive increment of fatigue striation spacing observed in the fractographic analyses.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Aluminum Alloy Microstructure Properties · Microstructure and mechanical properties · Fatigue and fracture mechanics
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (44)
Show source-provided references
1. Recent development in aluminium alloys for aerospace applications10.1016/S0921-5093(99)00674-7 ↗
2. Heat treatment of 7xxx series aluminium alloys – some recent developments10.1016/S1003-6326(14)63306-9 ↗
3. Recent advances in the development of aerospace materials10.1016/j.paerosci.2018.01.001 ↗
4. How aluminum changed the world: a metallurgical revolution through technological and cultural perspectives10.1016/j.techfore.2019.03.011 ↗
5. Low-cycle fatigue life of SiC-particulate-reinforced Al-Si cast alloy composites with tensile mean strain effects10.1016/S0142-1123(99)00099-7 ↗
6. Mean stress effects on low cycle fatigue for a high strength steel10.1111/j.1460-2695.1991.tb00672.x ↗
7. Sandor BI. Fundamentals of cyclic stress and strain. University of Wisconsin Press; 1972, ISBN: 978-0299061005.
8. Dynamic precipitation during cyclic deformation of an underaged Al–Cu alloy10.1016/j.msea.2011.06.037 ↗
9. Uniaxial mean stress relaxation of 9–12% Cr steel at high temperature: experiments and viscoplastic constitutive modeling10.1016/j.ijplas.2015.10.001 ↗
10. Modeling of cyclic ratcheting plasticity. Part 1: development of constitutive relations10.1115/1.2823355 ↗
11. Mean stress/strain effect on fatigue behavior of an epoxy resin10.1016/j.ijfatigue.2006.12.009 ↗
12. Mean stress relaxation during cyclic straining of high strength aluminum alloys10.1016/j.ijfatigue.2009.01.021 ↗
13. Strain ratio effects on low-cycle fatigue behavior and deformation microstructure of 2124–T851 aluminum alloy10.1016/j.msea.2014.03.040 ↗
14. Strain ratio effects on low-cycle fatigue behaviour of gravity cast Al-Si-Cu alloys10.1007/s11665-015-1656-1 ↗
15. Constitutive modeling of aluminum alloy 7050 cyclic mean stress relaxation and ratcheting10.1016/j.mechrescom.2013.08.001 ↗
16. Hu W, Wang CH, Barter S. Analysis of cyclic mean stress relaxation and strain ratcheting behaviour of aluminium 7050. Report DSTO-RR-153. Defence Science and Technology Organisation, Aeronautical and Maritime Research Laboratory, DSTR-RR-0153, Melbourne, Australia; 1999.
17. The relationship of microstructure to monotonic and cyclic straining of two age hardening aluminum alloys10.1007/BF02658827 ↗
18. Low-cycle fatigue of dissimilar friction stir welded aluminum alloys10.1016/j.msea.2015.11.075 ↗
19. Comparison of multiaxial fatigue damage models under variable amplitude loading10.1007/s12206-012-0872-y ↗
20. Fatigue damage and life evaluation of SS304 and Al 7050–T7541 alloys under various multiaxial strain paths by means of energy-based Fatigue damage models10.1016/j.mechmat.2016.04.007 ↗
21. Rusk DT, Taylor RE, Hoffman PC. Testing of 7050-T7451 Aluminium strain-life coupons for a probabilistic strain-life curve. Department of the Navy, Naval Air Warfare Center Aircraft Division, Maryland, Report NAWCADPAX/TR-2006/140; 2006.
22. The effect of tensile pre-straining on fatigue crack initiation mechanisms and mechanical behavior of AA7050 friction stir welds10.1016/j.msea.2018.08.104 ↗
23. Polmear IJ. Light alloys: from traditional alloys to nanocrystals. 4th ed., Butterworth-Heinemann, Elsevier; 2005, p. 125 and 137, ISBN 9780750663717.
24. Analysis of low cycle fatigue in AlMgSi aluminium alloys10.1016/j.engfailanal.2003.09.003 ↗
25. Early-stage precipitation in Al–Zn–Mg–Cu alloy (7050)10.1016/j.actamat.2004.06.025 ↗
26. Differential scanning calorimetry and thermodynamic predictions – a comparative study of Al-Zn-Mg-Cu alloys10.3390/met6080180 ↗
27. Low cycle fatigue test and enhanced lifetime estimation of high-strength steel S550 under different strain ratios10.1016/j.marstruc.2018.06.011 ↗
28. A study on the mean stress relaxation behavior of 2124–T851 aluminum alloy during low-cycle fatigue at different strain ratios10.1016/j.matdes.2014.11.018 ↗
29. Effect of tensile-mean-strain on plastic strain energy and cyclic response10.1115/1.3225786 ↗
30. Morrow J, Sinclair GM. Cycle-dependent stress relaxation. In: Symposium on basic mechanisms of fatigue. American Society for Testing and Materials. ASTM STP 237; 1958. p. 83–109.10.1520/STP39312S ↗
31. Cyclic stress–strain response and substructure10.1016/S0142-1123(01)00037-8 ↗
32. Low cycle fatigue properties of 2124/SiCp Al-alloy composites
33. Low cycle fatigue, fatigue crack propagation and substructures in a series of polycrystalline Cu-Al alloys10.1007/BF02642311 ↗
34. Energy-based approach for the evaluation of low cycle fatigue behaviour of 2.25Cr–1Mo steel at elevated temperature10.1016/j.msea.2010.05.011 ↗
35. A physically short fatigue crack growth approach based on low cycle fatigue properties10.1016/j.ijfatigue.2017.05.006 ↗
36. Generalized probabilistic model allowing for various fatigue damage variables10.1016/j.ijfatigue.2017.03.031 ↗
37. Fatigue life assessment of notched round bars under multiaxial loading based on the total strain energy density approach10.1016/j.tafmec.2017.06.003 ↗
38. Fatigue strength of severely notched specimens made of Ti–6Al–4V under multiaxial loading10.1111/ffe.12272 ↗
39. Strain energy gradient-based LCF life prediction of turbine discs using critical distance concept10.1016/j.ijfatigue.2018.04.006 ↗
40. Monotonic and cyclic behavior of DIN 34CrNiMo6 tempered alloy steel10.3390/met6050098 ↗
41. Low-cycle fatigue behavior of 10CrNi3MoV high strength steel and its undermatched welds10.3390/ma11050661 ↗
42. Effect of mean stress and ratcheting strain on fatigue life of steel10.1016/0142-1123(96)00088-6 ↗
43. Ellyin · 1997
44. The low-cycle fatigue and cyclic fracture behavior of 7150 aluminum alloy10.1016/0142-1123(91)90358-6 ↗