Determination of the Fatigue Properties of Aluminum Alloy Using Mini Specimen

Abstract:

There are situations where taking normative specimens is impossible due to the dimensions of the objects investigated (e.g. extruded sections) and one of the solutions is to use mini specimens. As for non-standard specimen testing, it is essential to define the effect of size on fatigue strength. The research methodology facilitates the determination of fatigue characteristics (S-N) for EN AW-6063 aluminum alloy. The material is used to manufacture the extruded section in the process of extrusion of the material through the extruding die. The methodology assumes the geometry of the mini specimen and the normative specimen. As for the material strength identification, a static tensile test for the specimens made directly from finished elements and preliminarily strained in cycles was carried out. As a result of the cyclic material reinforcement, an increase in yield strength Re was observed, which, in turn, rejects Re as the upper criterion of the high-cycle fatigue range. The essential fatigue tests were performed based on unilateral cyclic tension (R = 0.1). The effect of size on fatigue strength was defined. Theoretically aluminum alloy non-sensitive to changes in the size of the cross-section showed a different strength in mini and normative specimens.

• Periodical: Materials Science Forum (Volume 726)
• Pages: 63-68
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.726.63
• Online since: August 2012
• Authors: Tomasz Tomaszewski, Janusz Sempruch
• Keywords: Aluminium Alloy, Cyclic Hardening, High Cycle Fatigue (HCF), Mini Specimen

References

[1] PN-74/H-04327. Badanie metali na zmęczenie. Próba osiowego rozciągania – ściskania przy stałym cyklu obciążeń zewnętrznych.

[2] J. Sempruch, T. Tomaszewski, Application of mini specimens to high-cycle fatigue tests, Journal of Polish Cimac (2011) 279-287.

[3] T. Hirose, H. Sakasegawa, A. Kohyama, Y. Katoh, H. Tanigawa, Effect of specimen size on fatigue properties of reduced activation ferritic/martensitic steels, Journal of Nuclear Materials (2000) 283-287.

DOI: 10.1016/s0022-3115(00)00141-0

[4] Y. Furuya, Notable size effects on very high cycle fatigue properties of high-strength steel, Materials Science and Engineering A (2011) 5234-5240.

DOI: 10.1016/j.msea.2011.03.082

[5] M.D. Callaghan, S.R. Humphries, M. Law, M. Ho, K. Yan, W.Y. Yeung, Specimen-size dependency and modelling of energy evolution during high-temperature low-cycle fatigue of pressure vessel steel, Scripta Materialia (2011) 308-311.

DOI: 10.1016/j.scriptamat.2011.04.038

[6] D. Boroński, Lokalne własności materiałowe w analizie zmęczeniowej, 2009.

[7] S. Kocańda, J. Szala, Podstawy obliczeń zmęczeniowych, 1997.

[8] PN-EN ISO 6892-1:2010. Metale - Próba rozciągania - Część 1: Metoda badania w temperaturze pokojowej.

[9] J. Szala, Hipotezy sumowania uszkodzeń zmęczeniowych, 1998.

[10] A.A. Luo, R.C. Kubic, J.M. Tartaglia, Microstructure and fatigue properties of hydroformed aluminum alloys 6063 and 5754, Metallurgical and Materials Transactions A (2003) 2549-2557.

DOI: 10.1007/s11661-003-0014-3

[11] A. Neimitz, I. Dzioba, M. Graba, J. Okrajni, Ocena wytrzymałości, trwałości i bezpieczeństwa pracy elementów konstrukcyjnych zawierających defekty, 2008.