Effect of Different Scale Precipitates on Corrosion Behavior of Mg- 10Gd-3Y-0.4Zr Alloy

doi:10.1007/s40195-018-0792-7

Abstract

Abstract:

A large amount of directional and willow-like β′ phase was precipitated in Mg-10Gd-3Y-0.4Zr (GW103K) alloy after solution treatment and subsequently aged treatment (T6). In order to explore the effect of the precipitates on the corrosion behavior of the GW103K alloy, the alloy was subjected to solution treatment (T4) at 773 K for 4 h at first, subsequently aged at 498 K for 193 h (T6). The microstructure evolution of the GW103K alloy after this treatment was investigated by scanning electron microscopy and transmission electron microscopy. The high-angle annular detector dark-field scanning transmission electron microscopy was used to observe the typical corrosion morphologies of the nanoscale precipitation phases (β′) in the T6-treated alloy. The corrosion rate was measured by potentiodynamic polarization test. Combining with the potential measurement results by scanning Kelvin probe force microscopy, the effects of the skeleton-like Mg₂₄(Gd, Y)₅ and β′ precipitates on the corrosion behavior of GW103K alloy were explored. The results showed that the corrosion rate of the GW103K alloy in different conditions was ranked as: as-cast alloy> T4-treated alloy> T6-treated alloy, attributing to the fact that the relative potential differences of skeleton-like Mg₂₄(Gd, Y)₅ were lower than those of the matrix, therefore Mg₂₄(Gd, Y)₅ phase formed micro-galvanic coupling with the matrix and corrosion dissolution occurred. The nanoscale β′ precipitates in T6-treated alloy can retard the cathodic process.

Key words: Magnesium alloy, Aging precipitates, Corrosion, Potential difference, Transmission electron microscopy(TEM)

Shuang Yu, Rui-Ling Jia, Tao Zhang, Fu-Hui Wang, Jian Hou, Hui-Xia Zhang. Effect of Different Scale Precipitates on Corrosion Behavior of Mg- 10Gd-3Y-0.4Zr Alloy[J]. Acta Metallurgica Sinica (English Letters), 2019, 32(4): 433-442.

Figures/Tables 9

Fig. 1 SEM images and EDS analysis of GW103K alloys: a as-cast; b EDS analysis of skeleton-like phase in a; c T4 treatment; d T6 treatment

Fig. 2 TEM analysis for as-cast GW103K alloy: a bright-field image of skeleton-like phase; b SAED pattern of skeleton-like phase

Fig. 3 β′ phase in GW103K alloy after aging at 498 K for 193 h: a TEM image; b SAED pattern; c high-resolution TEM image taken along 〈0001〉Mg zone; d the corresponding FT patterns. The ring indicates the mask location used for inverse fast FT (FFT) and processed image after inverse FFT corresponding to c

Fig. 4 Potentiodynamic polarization curves of GW103K alloy in different conditions

Table 1 Electrochemical parameters obtained from potentiodynamic polarization curves

Material	E_corr (vs. SCE)	I_corr (A/cm²)	β_a (V/dec)	β_c (V/dec)	R_p (Ω cm²)
GW103K-F	-?1.389	1.78E-4	0.125	-?0.267	573.453
GW103K-T4	-?1.429	1.04E-4	0.116	-?0.253	894.756
GW103K-T6-193 h	-?1.449	7.21E-5	0.112	-?0.247	1145.033

Fig. 5 Corrosion morphologies of GW103K alloys in different conditions after immersion in 3.5 wt% NaCl solution for 10 min: a as-cast; b T4 treatment; c T6 treatment; dmetallographic image of T6-treated alloy immersed in 3.5 wt% NaCl solution for 30 min

Fig. 6 a HAADF image showing morphologies of β′ phases; b HAADF image showing corrosion morphologies of β′ phases after immersion in 1 mol/L NaCl solution for 15 min; cSEM image showing corrosion morphology of alloy after immersion in 3.5 wt% NaCl solution for 2 h for GW103K alloy in T6 condition

Fig. 7 AFM surface topographies a, d; 3D potential maps b, e; and potential profile of skeleton-like phases c, f in as-cast GW103K alloy a-c and GW103K alloy after aging treatment d-f

Fig. 8 Morphologies and potential map of β′ phase in t GW103K alloy after 193-h aging treatment: a HRTEM image; b AFM surface topography; c two-dimensional potential map; d line profile analysis corresponding to the line L3 shown in c

References

[1]	M.K. Kulekci, Int. J. Adv. Manuf. Technol. 39, 851(2008)
[2]	S.B. Shen, S. Cai, X.G. Bao, P. Xu, Y. Li, S. Jiang, G.H. Xu, Chem. Eng. J. 339, 7(2018)
[3]	X.R. Chen, F.K. Ning, J. Hou, Q.C. Le, Y. Tang, Ultrason. Sonochem. 40, 433(2018)
[4]	X.W. Liu, Y. Liu, B. Jin, Y. Lu, J. Lu, J. Mater. Sci. Technol. 33, 224(2017)
[5]	L.P. Zhong, Y.J. Wang, M. Gong, X.W. Zheng, J. Peng, Mater. Charact. 138, 284(2018)
[6]	D.F. Zhang, X. Chen, F.S. Pan, L.Y. Jiang, G.S. Hu, D.L. Yu, Funct. Mater. 45, 05001(2014)
[7]	R.L. Satet, M.J. Hoffmann, J. Am. Ceram. Soc. 88, 2485(2005)
[8]	Y.R. Wu, W.Y. Hu, L.X. Sun, J. Phys. D: Appl. Phys. 40, 7584(2007)
[9]	L.L. Tang, Y.H. Zhao, R.K. Islamgaliev, R.Z. Valiev, Y.T. Zhu, J. Alloys Compd. 721, 577(2017)
[10]	Y. Gao, Q.D. Wang, J.H. Gu, Y. Zhao, Y. Tong, J.Y. Kaneda, J. Rare Earths 26, 298 (2008)
[11]	X.B. Liu, R.S. Chen, E.H. Han, J. Alloys Compd. 465, 232(2008)
[12]	S.Q. Liang, D.K. Guan, X.P. Tan, L. Chen, Y. Tang, Mater. Sci. Eng., A 528, 1589 (2011)
[13]	Q. Wang, L. Xiao, W.C. Liu, H.H. Zhang, W.D. Cui, Z.Q. Li, G.H. Wu, Mater. Sci. Eng., A 705, 402 (2017)
[14]	S.Q. Liang, D.K. Guan, L. Chen, Z.H. Gao, H.X. Tang, X.T. Tong, R. Xiao, Mater. Des. 32, 361(2011)
[15]	H. Liu, Y. Gao, J.Z. Liu, Y.M. Zhu, Y. Wang, J.F. Nie, Acta Mater. 61, 453(2013)
[16]	D.K. Xu, E.H. Han, Y.B. Xu, Prog. Nat. Sci.-Mater. 26, 117(2016)
[17]	Y.X. Li, D. Qiu, Y.H. Rong, M.X. Zhang, Intermetallics 40, 45 (2013)
[18]	J.X. Zheng, Z. Li, L.D. Tan, X.S. Xu, R.C. Luo, B. Chen, Mater. Charact. 117, 76(2016)
[19]	Y.C. Wan, H.C. Xiao, S.N. Jiang, B. Tang, C.M. Liu, Z.Y. Chen, L.W. Lu, Mater. Sci. Eng., A 617, 243 (2014)
[20]	Y.W. Song, D.Y. Shan, E.H. Han, J. Mater. Sci. Technol. 33, 945(2017)
[21]	J.H. Liu, Y.W. Song, J.C. Chen, P. Chen, D.Y. Shan, E.H. Han, Electrochim. Acta 189, 190 (2016)
[22]	L.M. Peng, J.W. Chang, X.W. Guo, A. Atrens, W.J. Ding, Y.H. Peng, J. Appl. Electrochem. 39, 913(2009)
[23]	S.Q. Liang, D.K. Guan, X.P. Tan, Mater. Des. 32, 1194(2011)
[24]	J.Z. Zhang, Z.X. Ma, D.F. Li, Mater. Heat Treat. 38, 73(2007)
[25]	K. Zhang, X.G. Li, Y.J. Li, M.L. Ma, Trans. Nonferrous. Met. Soc. China 18, 12 (2008)
[26]	X.M. Zhang, Z.Y. Mu, Y.L. Deng, C.P. Tang, L.Q. Guan, J. Sci. Technol. 44, 2223(2013)
[27]	J. Zhao, J.P. Li, Y.C. Guo, Z. Yang, Y.M. Yang, M.X. Liang, Rare Met. Mater. Eng. 37, 281(2008)
[28]	L.Y. Wang, J. Huang, J. Dong, K. Feng, Y.X. Wu, P.K. Chu, Mater. Charact. 118, 486(2016)
[29]	T. Honma, T. Ohkubo, K. Hono, S. Kamado, Mater. Sci. Eng., A 395, 301 (2005)
[30]	C. Antion, P. Donnadieu, F. Perrard, A. Deschamps, C. Tassin, A. Pisch, Acta Mater. 51, 5335(2003)
[31]	J.X. Zheng, X.S. Xu, K.Y. Zhang, B. Chen, Mater. Lett. 152, 287(2015)
[32]	S.M. He, X.Q. Zeng, L.M. Peng, X. Gao, J.F. Nie, W.J. Ding, J. Alloys Compd. 421, 309(2006)