Neutron Diffraction and Acoustic Emission Study of Mg-Al-Sr Alloy Reinforced with Short Saffil^® Fibers Deformed in Compression

Abstract:

Neutron diffraction method has been applied in the ex-situ investigation of the residual stresses in Mg-5wt.%Al-1 wt.%Sr (AJ51) magnesium alloy reinforced with short Saffil® fibers deformed in compression at room temperature. The residual stresses were measured in the axial and radial directions with respect to the load direction. It is shown that in the initial state the tensile stress is present in the matrix phase. The in-situ acoustic emission measurements were performed with the aim to reveal the main deformation mechanisms operating in the particular stages of the plastic deformation. Ex-situ neutron diffractions experiments showed that the tensile axial residual stress in the matrix increases with increasing plastic deformation while the radial residual stress decreases. In situ acoustic emission measurements indicate that the main deformation mechanisms are twinning and glide of bigger dislocation ensembles in the early stages of the compressive deformation while the fibers breakage was observed in the vicinity of the maximum stress.

• Periodical: Materials Science Forum (Volume 777)
• Pages: 92-98
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.777.92
• Online since: February 2014
• Authors: Gergely Farkas*, Kristián Máthis, Petr Lukáš, Jan Pilch, Miroslav Vrána, Miloš Janeček, Zuzanka Trojanová
• Keywords: Acoustic Emission (AE), Magnesium Composite, Neutron Diffraction, Residual Stress

References

[1] N. Chawla, K.K. Chawla, Metal Matrix Composites, Springer, New York, 2006.

[2] N. Shi, R.J. Arsenault, Annu. Rev., Mater. Sci. 24 (1994) 321.

[3] Z. Trojanová, Z. Száraz, F. Chmelík, P. Lukáč, Mat. Sci. Eng. A-Struct, 528 (2011) 2479-2483.

DOI: 10.1016/j.msea.2010.11.058

[4] Z. Trojanová, V. Gärtnerová, A. Jäger, A. Námešný, M. Chalupová, P. Palček and P. Lukáč, Mechanical and fracture properties of an AZ91 Magnesium Alloy reinforced by Si and SiC particles, Comp. Science Technol. 69 (2009) 2256-2264.

DOI: 10.1016/j.compscitech.2009.06.016

[5] Z. Trojanová, Z. Száraz, P. Palček, M. Chalupová, Magnesium Alloys Based Composites, Magnesium alloys-Design, Processing and Properties. Ed. F. Czerwinski, INTECH (2011) 501-526.

DOI: 10.5772/67028

[6] M.E. Fitzpatrick, P.J. Withers, A. Baczmanski, M.T. Hutchings, R. Levy, M. Ceretti, A. Lodini, Acta Mater. 50 (2002) 1031–1040.

DOI: 10.1016/s1359-6454(01)00401-3

[7] P. Fernández-Castrillo, G. Bruno, G. González-Doncel, Mater. Sci. Eng. A 487 (2008) 26-32.

[8] K. Máthis and F. Chmelík (2012). Exploring Plastic Deformation of Metallic Materials by the Acoustic Emission Technique, Acoustic Emission, Dr. Wojciech Sikorski (Ed.), ISBN: 978-953-51-0056-0, InTech.

DOI: 10.5772/31660

[9] A. A. Pollock, Introduction to acoustic emission and a practical example, J. Environ. Sci., 22 (1979) 39-41.

[10] O. Muránsky, M. R. Barnett, D. G. Carr, S. C. Vogel, E. C. Oliver, Investigation of deformation twinning in a fine-grained and coarse-grained ZM20 Mg alloy: Combined in situ neutron diffraction and acoustic emission. Acta Mater. 58 (2010) 1503–1517.

DOI: 10.1016/j.actamat.2009.10.057

[11] M. E. Tuttle. Review of the concepts of stress, strain, and Hooke's Law, Dept. Mechanical Engineering, University of Washington, Seattle.

[12] R.F.S. Hearmon. The Elastic Constants of Anisotropic Materials II, Advan. Phys. 5 (1956) 323-382.

[13] M. T. Hutchings, , P. J. Withers, , T. M. Holden, and T. Lorentzen, Introduction to the Characterization of Residual Stress by Neutron Diffraction, Taylor & Francis, Boca Raton. 2005.

DOI: 10.1201/9780203402818

[14] F. Chmelik, J. Kiehn, P. Lukáč, K. U. Kainer, and B. L. Mordike, Acoustic emission and dilatometry for non-destructive characterisation of microstructural changes in Mg based metal matrix composites submitted to thermal cycling, Scripta Mater., 38(1) (1997) 81-87.

DOI: 10.1016/s1359-6462(97)00416-8

[15] Z. Jiang, J. Lian, D. Yang, S. Dong, Mater. Sci. Engn. A248 (1998) 256.

[16] J.A. Hartigan. Clustering algorithms. John Wiley & Sons, Inc. New York. 1975.

[17] A. Vinogradov, A. Lazarev, Continuous acoustic emission during intermittent plastic flow in alpha-brass, Scripta Mater. 66 (2012) 745-748.

DOI: 10.1016/j.scriptamat.2012.01.053

[18] T. Richeton, J. Weiss, F. Louchet, Dislocation avalanches: Role of temperature, grain size and strain hardening, Acta Mater. 53 (2005) 4463-4471.

DOI: 10.1016/j.actamat.2005.06.007

[19] K. Máthis, G. Farkas, M. Janeček, H. Choe. Acoustic emission study of Mg-Al-Sr alloy reinforced with short Saffil((R)) fibers deformed in compression, Mater. Sci. Eng., 575 (2013) 1-5.

DOI: 10.1016/j.msea.2013.03.045

[20] C. Scruby, H. N. G. Wadley, and J. E. Sinclair, The oirigin of acoustic-emission during deformation of aluminum and an aluminum-magnesium alloy, Philos. Mag. A 44(2) (1981) 249-274.

DOI: 10.1080/01418618108239532