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Corrosion Fatigue of AM50 and AE44 Alloys at Various Temperature and R-Ratio
Technical Paper
2006-01-0256
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Reported in this paper are the experimental results obtained from corrosion fatigue tests of high pressure die cast (HPDC) AM50 and AE44 magnesium specimens immersed in NaCl and GM9540P solutions at various temperature, low and high R-ratio. Test specimens were loaded under cyclic loading at temperature of −5°, 25°, and 80°C. It is shown that fatigue life was reduced significantly in these corrosive environments. Although the fatigue life (in air) is longer for specimens tested in −5°C in comparison with the ambient temperature data, the relative reduction of fatigue life in corrosive environments is much significant than that at 25°C.
An investigation of the effect of stress level on AM50 fatigue life shows that, for R=0.1, there is more loss in fatigue life, due to corrosion, when the applied stress is low; when the applied maximum stress is above the yield point, the reduction in fatigue life is relatively less significant. This trend is quite different from the oxidation effects on AM50 fatigue behavior at room temperature. This phenomenon is explained on the basis that pit evolution produced in the corrosive solution is the most dominant factor for fatigue crack initiation, and at lower stresses, there is more time allowed for corrosion to take place. Cyclic testing under very high stress (130% YS) and high R ratio (R=0.9) conditions showed a significant loss of fatigue life by the corrosion environment. Use of a two-layer conversion coating system on AE44 alloys improved considerably the fatigue life, however cracks can form when there is a breakdown in the coating. Further increase in fatigue life required a three-layer coating system.
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Citation
Fan, J., Zheng, W., Derushie, C., Zeng, X. et al., "Corrosion Fatigue of AM50 and AE44 Alloys at Various Temperature and R-Ratio," SAE Technical Paper 2006-01-0256, 2006, https://doi.org/10.4271/2006-01-0256.Also In
References
- Eliezer A. Gutman E. M. Abramov E. Aghion E. Corrosion fatigue and mechanical behavior of magnesium alloys Mordike B. L. Corrosion Reviews, Special Issue on Corrosion Resistance of Magnesium Alloys 16 Freund Publication House LtD London 1998 1 26
- Elizer A. Gutman E. M. Abramov E. Unigovski Ya. Corrosion fatigue of die-cast and extruded magnesium alloys Journal of Light Metals 1 2001 179 186
- Ross, P. MacCulloch, J. Clapp, C. Esdaile, R. The mechanical properties of anodized magnesium die castings SAE Technical Paper Series, 1999-01-0925
- Ferguson, W G Liu, W Ross, P MacCulloch, J Corrosion fatigue of high pressure die cast magnesium alloys Magnesium Technology 2001, 2001 TMS Annual Meeting New Orleans, LA; USA 11–15 Feb. 2001 269 274 2001
- Li, N. Osborne, R. Cox B. Penrod, D. Magnesium Engine Cradle – the USCAR Structural cast magnesium development project SAE 2005-01-0337
- Xu S. et al “Bolt-load retention of Mg alloys for automotive engine cradle applications” 283 288 Proc. of the 2nd International Light Metal Technology Conf. 2005
- Zheng Wenyue Osborne R. Derushie C. Lo J. Corrosion Protection of Structural Magnesium Alloys: Recent Development SAE 2005 Congress, SAE 2005-01-0732
- Wang X. Fan, J. An evaluation on the growth rate of small fatigue cracks in cast AM50 magnesium alloy at different temperature in vacuum conditions International Journal of Fatigue 28 2006 79 86
- Liao C. H. Particle-Induced Pitting Corrosion of Aluminum Alloys 1997
- OGAREVIC V. V. STEPHENS R.I Fatigue of Magnesium Alloys Annual Review of Materials Science 20 1990 141 177