Microstructure and Mechanical Properties of CNT-Reinforced AZ91D Composites Fabricated by Ultrasonic Processing

doi:10.1007/s40195-016-0438-6

Abstract

Abstract:

Carbon nanotube (CNT)-reinforced AZ91D alloy composite was fabricated by ultrasonic processing. The microstructure and mechanical properties of the CNTs/AZ91D composites were investigated. Obvious grain refinement was achieved with the addition of 0.5 wt% CNTs. The SEM observation indicated that CNTs were distributed near the grain boundary or around the inter-grain β-Mg₁₇Al₁₂ phase. No evident reaction product was found at the interface between CNTs and AZ91D matrix. Compared to the monolithic AZ91D alloy, the yield strength, ultimate tensile strength, and elongation of the 0.5 wt% CNTs/AZ91D composite were improved significantly. However, the poor interface bonding between CNTs and AZ91D matrix restricted further improvement in mechanical properties.

Key words: Carbon nanotubes (CNTs), Magnesium matrix composites, Ultrasonic vibration, Microstructure, Mechanical properties

Fu-Ze Zhao, Xiao-Hui Feng, Yuan-Sheng Yang. Microstructure and Mechanical Properties of CNT-Reinforced AZ91D Composites Fabricated by Ultrasonic Processing[J]. Acta Metallurgica Sinica (English Letters), 2016, 29(7): 652-660.

Figures/Tables 13

Table 1 Chemical composition of the commercial AZ91D (in wt%)

Al	Zn	Mn	Be	Fe	Cu	Si	Ni	Mg
8.89	0.62	0.32	0.0011	0.0017	0.0067	0.044	0.0005	Bal.

Fig. 1 SEM images of the raw CNTs a, b and AZ91D chips covered with CNTs c, d

Fig. 2 Optical micrographs of AZ91D and CNTs/AZ91D composite using polarized light: a AZ91D Type A; b AZ91D Type B; c 0.5 wt% CNTs/AZ91D composite

Fig. 3 SEM images of AZ91D Type A a, AZ91D Type B b, CNTs/AZ91D composite c and the XRD patterns of these samples d

Fig. 4 SEM image a and EDS analysis results b of the three phases in CNTs/AZ91D composites

Table 2 Area fraction of Mg17Al12 and Al8Mn5 in the three kinds of samples

Materials	Mg₁₇Al₁₂	Al₈Mn₅
AZ91D Type A	(6.71 ± 1.07) %	(0.16 ± 0.04) %
AZ91D Type B	(7.58 ± 0.40) %	(0.14 ± 0.02) %
0.5 wt% CNTs/AZ91D	(7.45 ± 1.28) %	(0.13 ± 0.03) %

Fig. 5 SEM images showing the distribution of CNTs in AZ91D: a CNTs are located near the eutectic phase at the grain boundary; b around the β-Mg17Al12 phase

Fig. 6 HAADF-STEM image a and HRTEM image b of the interface between a CNT and matrix

Table 3 Tensile properties of AZ91D and CNT/AZ91D composite

Material	YS (MPa)	UTS (MPa)	Elongation (%)
AZ91D Type A	109 ± 3	215 ± 2	7.0 ± 1.0
AZ91D Type B	115 ± 3	213 ± 2	7.5 ± 0.5
0.5 wt% CNTs/AZ91D	129 ± 2	230 ± 5	8.0 ± 0.5

Fig. 7 Representative stress-strain curves of AZ91D and CNTs/AZ91D composite

Fig. 8 Atomic arrangements of CNTs surface a and Mg (0002) crystal face b

Fig. 9 Hall-Petch relation of AZ91D alloy and the data point of CNTs/AZ91D composite

Fig. 10 Fracture surface of 0.5 wt% CNTs/AZ91D composite

References 27

[1]	R.A. Saravanan, M.K. Surappa, Mater. Sci. Eng. A 276, 108 (2000)
[2]	Q.C. Jiang, X.L. Li, H.Y. Wang, Scr. Mater. 48, 713(2003)
[3]	J. Lan, Y. Yang, X.C. Li, Mater. Sci. Eng. A 386, 284 (2004)
[4]	H.Y. Wang, Q.C. Jiang, Y. Wang, B.X. Ma, F. Zhao, Mater. Lett. 58, 3509(2004)
[5]	X.Q. Zhang, H.W. Wang, L.H. Liao, X.Y. Teng, N.H. Ma, Mater. Lett. 59, 2105 (2005)
[6]	Y. Wang, H.Y. Wang, K. Xiu, H.Y. Wang, Q.C. Jiang, Mater. Lett. 60, 1533(2006)
[7]	S.F. Hassan, A. Gupta, Mater. Sci. Eng. A 392, 163 (2005)
[8]	A.K. Chaubey, B.B. Jha, B.K. Mishra, Acta Metall. Sin (Engl. Lett.) 28, 444(2015)
[9]	B.G. Demczyk, Y.M. Wang, J. Cumings, M. Hetman, W. Han, A. Zettl, R.O. Ritchie, Mater. Sci. Eng. A 334, 173 (2002)
[10]	D. Zhou, F. Qiu, H. Wang, Q. Jiang, Acta Metall. Sin (Engl. Lett.) 27, 798(2014)
[11]	Y. Shimizu, S. Miki, T. Soga, I. Itoh, H. Todoroki, T. Hosono, K. Sakaki, T. Hayashi, Y.A. Kim, M. Endo, S. Morimoto, A. Koide, Scr. Mater. 58, 267(2008)
[12]	K. Kondoh, H. Fukuda, J. Umeda, H. Imai, B. Fugetsu, M. Endo, Mater. Sci. Eng. A 527, 4103 (2010)
[13]	H. Fukuda, K. Kondoh, J. Umeda, B. Fugetsu, Compos. Sci. Technol. 71, 705(2011)
[14]	C.S. Goh, J. Wei, L.C. Lee, A. Gupta, Mater. Sci. Eng. A 423, 153 (2006)
[15]	M. Paramsothy, X.H. Tan, J. Chan, R. Kwok, M. Gupta, Mater. Des. 45, 15(2013)
[16]	S. Liu, F. Gao, Q. Zhang, X. Zhu, W. Li, Trans. Nonferrous Met. Soc. 20, 1222(2010)
[17]	C.D. Li, X.J. Wang, W.Q. Liu, K. Wu, H.L. Shi, C. Ding, X.S. Hu, M.Y. Zheng, Mater. Sci. Eng. A 597, 264 (2014)
[18]	C.D. Li, X.J. Wang, W.Q. Liu, H.L. Shi, C. Ding, X.S. Hu, M.Y. Zheng, K. Wu, Mater. Des. 58, 204(2014)
[19]	H. Shi, X. Wang, C. Li, X. Hu, C. Ding, K. Wu, Y. Huang, Acta Metall. Sin (Engl. Lett.) 27, 909(2014)
[20]	L. Ci, Z. Ryu, N.Y. Acta Mater. 54, 5367(2006)
[21]	Q. Li, A. Viereckl, C.A. Rottmair, R.F. Singer, Compos. Sci. Technol. 69, 1193(2009)
[22]	X. Liu, Y. Osawa, S. Takamori, T. Mukai, Mater. Sci. Eng. A 487, 120 (2008)
[23]	P. Kim, L. Shi, A. Majumdar, P.L. Phys. Rev. Lett. 87, 215502(2001)
[24]	M.J. Shen, X.J. Wang, C.D. Li, M.F. Zhang, X.S. Hu, M.Y. Zheng, K. Wu, Mater. Des. 52, 1011(2013)
[25]	M.J. Shen, X.J. Wang, C.D. Li, M.F. Zhang, X.S. Hu, M.Y. Zheng, K. Wu, Mater. Des. 54, 436(2014)
[26]	H.J. Ryu, S.I. Cha, S.H. Hong, J. Mater. Res. 18, 2851(2003)
[27]	S.R. Bakshi, D. Lahiri, A. Agarwal, Int. Mater. Rev. 55, 41(2010)