Ageing Response of Powder Metallurgy AZ91 and AZ91 Reinforced with Multiwall Carbon Nanotube

Abstract:

Powder metallurgy metal matrix composites based on AZ91 alloy matrix reinforced with 0.3, 0.6 and 0.9 weight percent of multiwall carbon nanotube (MWCNT) were investigated from the point of view of their response to artificial ageing as compared to the unreinforced AZ91 matrix alloy. Mg-Zn-Al (AZ91) and its composite were prepared by milling the raw materials and followed by sintering at 450°C for 2 hours. The sintered samples were solution treated at 415°C for 2 hours and followed by artificial ageing at 175°C. The ageing behavior was monitored by following the phase analysis and hardness of the samples examined. Microstructure of the sintered composites indicated that MWCNT was embedded in the AZ91 matrix alloy. All composites indicated lower hardness than matrix, however AZ91reinforced with 0.6 and 0.9 weight percent of CNT showed accelerated ageing. X-ray diffraction pattern indicated the present of β-phase (Mg₁₇Al₁₂) that responsible for the hardening behavior.

• Periodical: Materials Science Forum (Volume 857)
• Pages: 261-265
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.857.261
• Online since: May 2016
• Authors: Nur Hidayah Ahmad Zaidi, J.B. Shamsul, K.R. Ahmad, Sinar Arzuria Adnan, Ahmad Mujahid Ahmad Zaidi
• Keywords: AZ91, Hardness, Heat Treatment, Microstructure

References

[1] Goh, C. S., Wei, J., Lee, L. C., & Gupta, M. (2006). Simultaneous enhancement in strength and ductility by reinforcing magnesium with carbon nanotubes. Materials Science and Engineering A, 423, 153–156. doi: 10. 1016/j. msea. 2005. 10. 071.

DOI: 10.1016/j.msea.2005.10.071

[2] S. Iijima, (1991). Herical microtubules of graphitic carbon. Nature 354, 56 - 58; doi: 10. 1038.

[3] Jayakumar, J., Raghunath, B. K., & Rao, T. H. (2013). Enhancing microstructure and mechanical properties of AZ31-MWCNT nanocomposites through mechanical alloying. Advances in Materials Science and Engineering, 2013. doi: 10. 1155/2013/539027.

DOI: 10.1155/2013/539027

[4] Shimizu, Y., Miki, S., Soga, T., Itoh, I., Todoroki, H., Hosono, T. Koide, a. (2008). Multi-walled carbon nanotube-reinforced magnesium alloy composites. Scripta Materialia, 58, 267–270. doi: 10. 1016/j. scriptamat. 2007. 10. 014.

DOI: 10.1016/j.scriptamat.2007.10.014

[5] Hwang, S., Nishimura, C., & McCormick, P. G. (2001). Compressive mechanical properties of MgTi-C nanocomposite synthesised by mechanical milling. Scripta Materialia, 44, 2457–2462. doi: 10. 1016/S1359-6462(01)00925-3.

DOI: 10.1016/s1359-6462(01)00925-3

[6] N. Saheb, A. Kahlil, A.S., Hakeem, T. Loaoi, N. Al-Aqeeli, A.M., Al-Qutub (2013). Age Behaviour of Carbon Nanotube Reinforced Aluminum Nanocomposites. Journal of Nano Research , 21, 29-35. doi: 10. 4028/www. sciencetific. net/JNanoR. 21. 29.

DOI: 10.4028/www.scientific.net/jnanor.21.29

[7] Saheb, N., Qadir, N. U., Siddiqui, M. U., Fazl, A., Arif, M., Akhtar, S. S., & Al-aqeeli, N. (2014). Characterization of Nanoreinforcement Dispersion in Inorganic Nanocomposites: A Review, 4148–4181. doi: 10. 3390/ma7064148.

DOI: 10.3390/ma7064148

[8] C. Badini, F. Marino, M. Montorsi, & X.B. Guo, (1992). Precipitation Phenomena in B4C-reinforced Magnesium-Based Composite. Materials Science & Engineering, A157, 53-61. Doi: 10. 1016/0921-5093(92)90098-L.

DOI: 10.1016/0921-5093(92)90098-l

[9] F. Sahnoune, M. Fatmi, H. Belhouchet, M. Heraiz, & N. Saheb, (2013). Kinetics and Microstructure of Solid Phase Precipitation in Mg-7 wt. %Al, International Journal of Advance Industrial Engineering, 54-58.

[10] J. B. Clark, (1968). Age hardening in a Mg. 9wt% Al Alloy. Acta Metallurgica, 16, 141-152.

DOI: 10.1016/0001-6160(68)90109-0

[11] A. F. Crawley and K. S. Milliken, (1974). Precipitate Morphology and Orientation Relationship in an Aged Mg-9% Al-1% Zn-0. 3% Mn Alloys. Acta Metallurgica, 22, 557-562.

DOI: 10.1016/0001-6160(74)90152-7

[12] C. R. Brooks, (1982). Heat Treatment, Structures and Properties of Non-ferrous Alloys, Ed. American Society for Metals, Metals Park, OH, p.260.