This study is aimed at understanding the tensile ductility and compressive strength-enhancing dual function of nanoparticles in a concentrated magnesium alloy (AZ81) nanocomposite. Si3N4 nanoparticles were selected for reinforcement purposes due to the known affinity between magnesium and nitrogen. AZ81 magnesium alloy was reinforced with Si3N4 nanoparticles using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size and hardness to the monolithic alloy, reasonable nanoparticle distribution, and nondominant (0 0 0 2) texture in the longitudinal direction. Compared to the monolithic alloy in tension, the nanocomposite exhibited higher failure strain (+23%) without significant compromise in strength, and higher energy absorbed until fracture (EA) (+27%). Compared to the monolithic alloy in compression, the nanocomposite exhibited similar failure strain (+3%) with significant increase in strength (up to +20%) and higher EA (+24%). The beneficial effects of Si3N4 nanoparticle addition on tensile ductility and compressive strength dual enhancement of AZ81 alloy are discussed in this paper. 1. Introduction Silicon nitride nanoparticles in the shape of near-spheres and wires have been synthesized by chemical vapor deposition (CVD) [1, 2]. In the case of nanowires, the catalytic properties of metal nanoparticles were utilized during CVD to promote the directed silicon nitride growth at nanoscale [2]. On one hand, nanoparticles are active towards cells (or bioactive), where the specific biological function at cellular level can be disrupted, modified (negatively or positively), or promoted by the uncoated nanoparticles present [3]. On the other hand, silicon nitride nanoparticles have been coated and chemically stabilized prior to effective dispersion in a rubber matrix [4]. In the context of mechanical (crystallographic structure related) or functional (electronic structure related) properties, the function of nanoparticles in a metallic matrix is related to (a) nanoparticle-matrix reactivity and (b) nanoparticle distribution in the matrix. Magnesium alloys are an easily available lightweight and energy saving metallic matrix. In particular, the AZ (Aluminium-Zinc) series of magnesium alloys are characterized by (a) low cost, (b) ease of handling, (c) good strength and ductility, and (d) resistance to atmospheric corrosion [5]. These qualities enable the common use of AZ series magnesium alloys [5]. Regarding magnesium nanocomposites, the friction stir processing technique has been used to add SiO2 nanoparticles to
References
[1]
C.-S. Kim, W.-K. Youn, D.-K. Lee, K.-S. Seol, and N.-M. Hwang, “Low-temperature deposition of crystalline silicon nitride nanoparticles by hot-wire chemical vapor deposition,” Journal of Crystal Growth, vol. 311, no. 15, pp. 3938–3942, 2009.
[2]
H. Y. Kim, J. Park, and H. Yang, “Synthesis of silicon nitride nanowires directly from the silicon substrates,” Chemical Physics Letters, vol. 372, no. 1-2, pp. 269–274, 2003.
[3]
Y. F. Zhang, Y. F. Zheng, and L. Qin, “A comprehensive biological evaluation of ceramic nanoparticles as wear debris,” Nanomedicine: Nanotechnology, Biology, and Medicine, vol. 7, no. 6, pp. 975–982, 2011.
[4]
Y. Tai, J. Miao, J. Qian, R. Xia, and Y. Zhang, “An effective way to stabilize silicon nitride nanoparticles dispersed in rubber matrix by a one-step process,” Materials Chemistry and Physics, vol. 112, no. 2, pp. 659–667, 2008.
[5]
M. M. Avedesian and H. Baker, ASM Specialty Handbook: Magnesium and Magnesium Alloys, ASM International, Materials Park, Ohio, USA, 1999.
[6]
C. J. Lee, J. C. Huang, and P. J. Hsieh, “Mg based nano-composites fabricated by friction stir processing,” Scripta Materialia, vol. 54, no. 7, pp. 1415–1420, 2006.
[7]
Y. Feng, X. Zhou, Z. Min, and W. Kun, “Superplasticity and texture of SiC whiskers in a magnesium-based composite,” Scripta Materialia, vol. 53, no. 3, pp. 361–365, 2005.
[8]
T. G. Nieh, A. J. Schwartz, and J. Wadsworth, “Superplasticity in a 17 vol.% SiC particulate-reinforced ZK60A magnesium composite (ZK60/SiC/17p),” Materials Science and Engineering A, vol. 208, no. 1, pp. 30–36, 1996.
[9]
M. Paramsothy, S. F. Hassan, N. Srikanth, and M. Gupta, “Enhancing tensile/compressive response of magnesium alloy AZ31 by integrating with Al2O3 nanoparticles,” Materials Science and Engineering A, vol. 527, no. 1-2, pp. 162–168, 2009.
[10]
M. Paramsothy, S. F. Hassan, N. Srikanth, and M. Gupta, “Simultaneous enhancement of tensile/compressive strength and ductility of magnesium alloy AZ31 using carbon nanotubes,” Journal of Nanoscience and Nanotechnology, vol. 10, no. 2, pp. 956–964, 2010.
[11]
M. Paramsothy, J. Chan, R. Kwok, and M. Gupta, “Enhanced mechanical response of hybrid alloy AZ31/AZ91 based on the addition of Si3N4 nanoparticles,” Materials Science and Engineering A, vol. 528, no. 21, pp. 6545–6551, 2011.
[12]
M. Paramsothy, J. Chan, R. Kwok, and M. Gupta, “TiC nanoparticle addition to enhance the mechanical response of hybrid magnesium alloy,” Journal of Nanotechnology, vol. 2012, Article ID 401574, 9 pages, 2012.
[13]
M. De Cicco, H. Konishi, G. Cao et al., “Strong, ductile magnesium-zinc nanocomposites,” Metallurgical and Materials Transactions A, vol. 40, no. 12, pp. 3038–3045, 2009.
[14]
L. M. Tham, M. Gupta, and L. Cheng, “Influence of processing parameters during disintegrated melt deposition processing on near net shape synthesis of aluminium based metal matrix composites,” Materials Science and Technology, vol. 15, no. 10, pp. 1139–1146, 1999.
[15]
M. Gupta, M. O. Lai, and S. C. Lim, “Regarding the processing associated microstructure and mechanical properties improvement of an Al–4.5 Cu alloy,” Journal of Alloys and Compounds, vol. 260, no. 1-2, pp. 250–255, 1997.
[16]
S. F. Hassan and M. Gupta, “Effect of particulate size of Al2O3 reinforcement on microstructure and mechanical behavior of solidification processed elemental Mg,” Journal of Alloys and Compounds, vol. 419, no. 1-2, pp. 84–90, 2006.
[17]
S. F. Hassan and M. Gupta, “Development of nano-Y2O3 containing magnesium nanocomposites using solidification processing,” Journal of Alloys and Compounds, vol. 429, no. 1-2, pp. 176–183, 2007.
[18]
G. E. Dieter, Mechanical Metallurgy, McGraw-Hill, London, UK, SI Metric edition, 1998.
[19]
S. F. Hassan and M. Gupta, “Effect of different types of nano-size oxide participates on microstructural and mechanical properties of elemental Mg,” Journal of Materials Science, vol. 41, no. 8, pp. 2229–2236, 2006.
[20]
S. F. Hassan and M. Gupta, “Enhancing physical and mechanical properties of Mg using nanosized Al2O3 particulates as reinforcement,” Metallurgical and Materials Transactions A, vol. 36, no. 8, pp. 2253–2258, 2005.
[21]
Z. Száraz, Z. Trojanová, M. Cabbibo, and E. Evangelista, “Strengthening in a WE54 magnesium alloy containing SiC particles,” Materials Science and Engineering A, vol. 462, no. 1-2, pp. 225–229, 2007.
[22]
L. H. Dai, Z. Ling, and Y. L. Bai, “Size-dependent inelastic behavior of particle-reinforced metal-matrix composites,” Composites Science and Technology, vol. 61, no. 8, pp. 1057–1063, 2001.
[23]
D. Hull and D. J. Bacon, Introduction to Dislocations, Butterworth-Heinemann, Oxford, UK, 4th edition, 2002.
[24]
T. Laser, C. Hartig, M. R. Nürnberg, D. Letzig, and R. Bormann, “The influence of calcium and cerium mischmetal on the microstructural evolution of Mg–3Al–1Zn during extrusion and resulting mechanical properties,” Acta Materialia, vol. 56, no. 12, pp. 2791–2798, 2008.
[25]
J. Bohlen, S. B. Yi, J. Swiostek, D. Letzig, H. G. Brokmeier, and K. U. Kainer, “Microstructure and texture development during hydrostatic extrusion of magnesium alloy AZ31,” Scripta Materialia, vol. 53, no. 2, pp. 259–264, 2005.
