Effect of Si Content on the Fatigue Fracture Behavior of Wrought Al-xSi-0.7Mg Alloy

Abstract:

The wrought Mg-containing high-silicon aluminum alloy has become more attractive as an ideal structural material, because it has moderate strength and the ductility, high wear and corrosion resistance, low thermal expansion coefficient and low cost. However, as structural material, the fatigue properties and the fatigue fracture behavior of it should be paid much more attention to, especially the effect of Si content on the fatigue properties of wrought Mg-containing Al-Si alloy. In this paper, the wrought Al-(1.44%, 4.92%, 6.61%, 8.81% and 12.4%)Si-0.7%Mg alloy were prepared through DCC and homogenization treatment, and then hot-rolled and cold-rolled into 1.3mm sheets. The microstructure and fatigue fracture morphology of Al-(1.44~12.4)Si-0.7Mg-T4 alloy sheet after fatigue test were investigated by LSCM and SEM. The results showed that the size of Si particles in Al-(1.44~12.4)Si-0.7Mg alloy sheets was approximately the same, but the number of Si particles increased as the Si content increased. The size of recrystallization grain in Al-(1.44~12.4)Si-0.7Mg alloy sheets decreased from 47μm to 10μm when Si content increased from 1.44% to 12.4%, which indicates that increasing of Si content can refine the grain of Al-(1.44~12.4)Si-0.7Mg alloy sheets. With the increasing of Si content the propagation area of fatigue fracture surface of Al-(1.44~12.4)Si-0.7Mg alloy sheets in T4 temper became rougher, and crack propagation became more difficult. Moreover, dimples in the fast fracture area became larger in amount, smaller in size and more uniform in distribution.

• Periodical: Materials Science Forum (Volume 941)
• Pages: 1143-1148
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.1143
• Online since: December 2018
• Authors: Guang Dong Wang, Ni Tian*, Chong Li, Gang Zhao, Liang Zuo
• Keywords: Fast Fracture Area, Fatigue Crack Propagation Area, Mg-Containing Al-Si Alloy Sheet, Si Particles, T4 Temper

References

[1] W. Li, Z. Chen, C. Ding, et al. Growth behavior of fatigue crack in spray-formed SiCp/Al-7Si composite, Acta Metall. Sinica. 47 (2011) 102-108.

[2] C.H. Li. Research on high-cycle fatigue behavior of spray deposited SiCp/Al-20Si composite, J. Mech. Eng. 48 (2012) 40.

DOI: 10.3901/jme.2012.10.040

[3] J.Z. Yi, P.D. Lee, T.C. Lindley, et al. Statistical modeling of microstructure and defect population effects on the fatigue performance of cast A356-T6 automotive components, Mater. Sci. Eng. A. 432 (2006) 59-68.

DOI: 10.1016/j.msea.2006.07.003

[4] C.H. Caceres, C.J. Davidson, J.R. Griffiths. The effect of Mg on the microstructure and mechanical behavior of Al-Si-Mg casting alloys, Metall. Mater. Trans. A. 30 (1999) 2611-2618.

DOI: 10.1007/s11661-999-0301-8

[5] X.S. Jiang, H.E. Guo-Qiu, B. Liu, et al. Microstructure-based analysis of fatigue behavior of Al-Si-Mg alloy, Trans. Nonferrous Met. Soc. China. 21 (2011) 443-448.

DOI: 10.1016/s1003-6326(11)60734-6

[6] G.S. Ham, M.S. Baek, J.H. Kim, et al. Effect of heat treatment on tensile and fatigue deformation behavior of extruded Al-12 wt%Si alloy, Met. Mater. Int. 23 (2017) 35-42.

DOI: 10.1007/s12540-017-6351-3

[7] L. Zuo, F.X. Yu, Y. Li, Y.L. Yang, G. Zhao and X. Zhao, China Patent 101,333,614 A. (2008).

[8] S.J. Hong, H.M. Kim, D. Huh. Effect of clustering on the mechanical properties of SiC particulate-reinforced aluminum alloy 2024 metal matrix composites, Mater. Sci. Eng. A. 347 (2003) 198-204.

DOI: 10.1016/s0921-5093(02)00593-2

[9] D.J. Lloyd. Aspects of particle fracture in particulate reinforced MMCs, Acta Metall. Et Mater. 39 (1991) 59-71.

[10] P. Jin, Y. Liu, S. Li, et al. Effects of SiC particle size on tensile property and fracture behavior on particle reinforced aluminum metal matrix composites[J]. Chin. J. Mater. Research. 23(2009) 211-214.

[11] F.T. Lee, J.F. Major, F.H. Samuel. Effect of silicon particles on the fatigue crack growth characteristics of Al-12 Wt Pct Si-0.35 Wt Pct Mg-(0 to 0.02) Wt Pct Sr casting alloys, Metall. Mater. Trans. A. 26 (1995) 1553-1570.

DOI: 10.1007/bf02647606

[12] J.G. Li, W.Y. Yang. Crack initiation and propagation in A356 aluminium alloy, Light Alloy Fabrication Technology, 30 (2002) 30-34.

[13] R.E. Wang, X.D. Hui, J.G. Wang, et al. Effects of precipitates on the fracture behavior of cast eutectic Al-Si alloys, Journal of University of Science & Technology Beijing, 33 (2011) 1508-1515.

[14] J.W. Liu, Y.Y. Tu, Y.Q. Sun, et al. Effects of precipitates on recrystallized structure in 3003 aluminum foils, Special Casting & Nonferrous Alloys, 29 (2009) 1067-1069.

[15] Y. Birol. Thermomechanical processing of a twin-roll cast Al-1Fe-0.2Si alloy, J. Mater. Process. Technol. 202 (2008) 564-568.

DOI: 10.1016/j.jmatprotec.2007.09.047

[16] H. Chang, X, Wang, X. Hu, et al. Effects of reinforced particles on dynamic recrystallization of Mg base alloys during hot extrusion, Rare Met. Mater. Eng. 43 (2014) 1821-1825.

DOI: 10.1016/s1875-5372(14)60138-7

[17] C.D. Marioara, S.J. Andersen, J. Jansen, et al. The influence of temperature and storage time at RT on nucleation of the β" phase in a 6082 Al-Mg-Si alloy, Acta Mater. 51 (2003) 789-796.

DOI: 10.1016/s1359-6454(02)00470-6