Surface Characteristics Improvement of AZ31B Magnesium by Surface Compositing with Carbon Nano-tubes through Friction Stir Processing

Subject Areas : Mechanical Engineering

M. Soltani ¹ , M. Shamanian ² , B. Niroumand ³

1 - Department of Materials Engineering, Isfahan University of Technology, Iran
2 - Department of Materials Engineering, Isfahan University of Technology, Iran
3 - Department of Materials Engineering, Isfahan University of Technology, Iran

Received: 2014-10-29 Accepted : 2014-12-20 Published : 2015-03-01

Keywords: Carbon Nano Tube (CNT), Friction Stir Processing (FSP), Surface Composite, Zener-Holloman Parameter,

Abstract :

In this research, the compositing of the surface of AZ31B magnesium alloy with CNT was studied by FSP. The parameters under study were rotational speed (500-1500 rpm), transverse speed (12-44 mm/min), number of passes (1-4), and CNT weight fraction (0-2%). Microhardness testing, optical metallography, FESEM, and EDS analysis were employed for the characterization of the samples. The suitable limits for the transverse speed and rotational speed were 12-24mm/min and 870-1140 rpm, respectively. The highest hardness in the FSP without compositing was assigned to the transverse speed of 24 mm/min and rotational speed of 870 rpm with a hardness of about 60 Vickers and the stir region grain size of less than 5 microns. The Zener-Holman parameter was calculated for computation and the least value was related to the conditions of the transverse speed of 12-24 mm/min and rotational speed of 870 rpm; as a result, the samples with the finest grain size were theoretically and experimentally specified. The most homogenous structure with the highest hardness was related to the three-pass state with a hardness of 69 Vickers. The best rate was the CNT weight percentage with a %2 weight enjoying the highest hardness. The FESEM images confirmed the suitable distribution of CNTs in the background after the performance of the three-pass processing.

References:

[1]   Zhang, D. T., Xiong, F., Zhang W. W., Qui, C., and Zhang, W., “Superplasticity of AZ31 Magnesium Alloy Prepared by Friction Stir Processing”, Transactions of Nonferrous Metals Society of China, Vol. 21, 2011, pp. 1911-1916.

[2]   Gray, J. E., Luan, B., “Protective Coatings on Magnesium and Its Alloys: A Critical Review”, Journal of Alloys and Compounds, Vol. 336, 2002, pp. 88-113.

[3]   Lim, D. K., Shibayanagi, T., and Gerlich, A. P., “Synthesis of Multi-Walled CNT Reinforced Aluminium Alloy Composite via Friction Stir Processing”, Materials Science and Engineering A, Vol. 507, 2009, pp. 194-199.

[4]   Woo, W., Choo, H., Brown, D. W., Liaw, P. K., and Feng, Z., “Texture Variation and Its Influence on the Tensile Behavior of a Friction-Stir Processed Magnesium Alloy”, Scripta Materialia, Vol. 54, 2006, pp. 1859-1864.

[5]   Darras, B. M., “A Model to Predict the Resulting Grain Size of Friction-Stir-Processed AZ31 Magnesium Alloy”, Journal of Materials Engineering and Performance, Vol. 21, No. 7, 2012, pp. 1243-1248.

[6]   Du, X. H., Wu, B.L., “Using Two-Pass Friction Stir Processing to Produce Nanocrystalline Microstructure in AZ61 Magnesium Alloy”, Science in China Series E: Technological Sciences, Vol. 52, No.6, 2009, pp. 1751-1755.

[7]   Woo, W., Choo, H., Prime. M. B., Feng, Z., and Clausen, B., “Microstructure, Texture and Residual Stress in a Friction-Stir-Processed AZ31B Magnesium Alloy”, Acta Materialia, Vol 56, 2008, pp. 1701-1711.

[8]   Faraji, G., Dastani, O., and Akbari Mousavi, S. A. A., “Effect of Process Parameters on Microstructure and Micro-Hardness of AZ91/Al₂O₃ Surface Composite Produced by FSP”, Journal of Materials Engineering and Performance, Vol. 20, No. 9, 2011, pp. 1583-1590.

[9]   Asadi, P., Faraji, G., and Besharati, M. K., “Producing of AZ91/SiC Composite by Friction Stir Processing (FSP)”, International Journal of Advanced Manufacturing Technology, Vol. 51, 2010, pp. 247-260.

[10]     Asadi, P., Faraji, G., Masoudi, A., and Besharati Givi, M. K., “Experimental Investigation of Magnesium-Based Nanocomposite Produced by Friction Stir Processing: Effects of Particle Types and Number of Friction Stir Processing Passes”, Metallurgical and Material Transactions A, Vol. 42A, 2011, pp. 2820-2832.

[11]     Lee, C. J., Huang, J. C., and Hsieh, P. J., “Mg Based Nano-Composites Fabricated by Friction Stir Processing”, Scripta Materialia, Vol. 54, 2006, pp. 1415–1420.

[12]     Izadi, H., Gerlich, A. P., “Distribution and Stability of Carbon Nanotubes during Multi-Pass Friction Stir Processing of Carbon Nanotube/Aluminum Composites”, Carbon, Vol. 50, 2012, pp. 4744-4749.

[13]     Johannes, L. B., Yowell, L. L., Sosa, E., Arepalli, S., and Mishra, R. S., “Survivability of Single-Walled Carbon Nanotubes during Friction Stir Processing”, Nanotechnology, Vol. 17, 2006, pp. 3081-3084.

[14]     Liu, Q., Ke, L., Liu, F., Huang, C., and Xing, Li., “Microstructure and Mechanical Property of Multi-Walled Carbon Nanotubes Reinforced Aluminum Matrix Composites Fabricated by Friction Stir Processing”, Materials and Design, Vol. 45, 2013, pp. 343-348.

[15]     Housh, S., Mikucki, B., “Properties and Selection: Nonferrous Alloys and Special-Purpose Materials: Selection and Application of Magnesium and Magnesium Alloys”, United States of America: ASM International, ASM Handbook, Vol. 2, 1990, Chap. 1.

[16]     Becherer, B. A., Witheford, T. J., “Heat Treating: Heat Treating of Ultrahigh-Strength Steels”, United States of America: ASM International, ASM Handbook, Vol. 4, 1991, Chap. 1.

[17]     Azizieh, M., Kokabi, A. H., and Abachi, A., “Effect of Rotational Speed and Probe Profile on Microstructure and Hardness of AZ31/Al₂O₃ Nanocomposites Fabricated by Friction Stir Processing”, Materials and Design, Vol. 32, 2011, pp. 2034-2041.

[18]     Yu, Z., Zhang, W., Choo, H., and Feng, Z., “Transient Heat and Material Flow Modelling of Friction Stir Processing of Magnesium Alloy Using Threaded Tool”, Metallurgical and Materials Transactions A, Vol. 43, 2011, pp. 724-737.

[19]     Alavi Nia, A., Omidvar, H., and Nourbakhsh, S. H., “Investigation of the Effects of Thread Pitch and Water Cooling Action on the Mechanical Strength and Microstructure of Friction Stir Processed AZ31”, Materials & Design, Vol. 52, 2013, pp. 615-620.

[20]     Chang, C. I., Du, X. H., and Huang, J. C., “Producing Nanograined Microstructure in Mg–Al–Zn Alloy by Two-Step Friction Stir Processing”, Scripta Materialia, Vol. 59, No. 3, 2008, pp. 356-359.

[21]     Chang, C. I., Du, X. H., and Huang, J. C., “Achieving Ultrafine Grain Size in Mg–Al–Zn Alloy by Friction Stir Processing”, Scripta Materialia, Vol. 57, No. 3, 2007, pp. 209-212.

[22]     Yu, Z., Choo, H., Feng, Z., and Vogel, S. C., “Influence of Thermo-Mechanical Parameters on Texture and Tensile Behavior of Friction Stir Processed Mg Alloy”, Scripta Materialia, Vol. 63, No. 11, 2010, pp. 1112-1115.