Hierarchical microstructure and two-stage corrosion behavior of a high-performance near-eutectic Zn-Li alloy

doi:10.1016/j.jmst.2020.10.076

Abstract

Abstract:

In order to improve mechanical and corrosion properties of biodegradable pure Zn, a knowledge-based microstructure design is performed on Zn-Li alloy system composed of hard β-LiZn ₄ and soft Zn phases. Precipitation and multi-modal grain structure are designed to toughen β-LiZn ₄ while strengthen Zn, resulting in high strength and high ductility for both the phases. Needle-like secondary Zn precipitates form in β-LiZn ₄, while fine-scale networks of string-like β-LiZn ₄ precipitates form in Zn with a tri-modal grain structure. As a result, near-eutectic Zn-0.48Li alloy with an outstanding combination of high strength and high ductility has been fabricated through hot-warm rolling, a novel fabrication process to realize the microstructure design. The as-rolled alloy has yield strength (YS) of 246 MPa, the ultimate tensile strength (UTS) of 395 MPa and elongation to failure (EL) of 47 %. Immersion test in simulated body fluid (SBF) for 30 days reveals that Li-rich products form preferentially at initial stage, followed by Zn-rich products with prolonged time. Aqueous insoluble Li₂CO₃ forms a protective passivation film on the alloy surface, which suppresses the average corrosion rate from 81.2 μm/year at day one down dramatically to 18.2 μm/year at day five. Afterwards, the average corrosion rate increases slightly with decrease of Li₂CO₃ content, which undulates around the clinical requirements on corrosion resistance (i.e., 20 μm/year) claimed for biodegradable metal stents.

Key words: Zn alloy, Microstructure design, Mechanical properties, Interfacial structure, Corrosion passivation

Zhen Li, Zhang-Zhi Shi, Hai-Jun Zhang, Hua-Fang Li, Yun Feng, Lu-Ning Wang. Hierarchical microstructure and two-stage corrosion behavior of a high-performance near-eutectic Zn-Li alloy[J]. J. Mater. Sci. Technol., 2021, 80: 50-65.

Figures/Tables 19

Fig. 1. (a) A sketch of the designed microstructure. (b) The Zn-rich end of Zn-Li phase diagram [50] with the region of eutectic reaction enlarged and crystal structures of Zn and β-LiZn4 [51,52]. (c) Engineering strain-stress curves of three parallel tensile samples of the Zn-Li alloy (WR). (d) Measuring the necking zone of a representative fractured tensile sample.

Table 1 Room temperature tensile properties of the alloy. C and WR refer to the as-cast and the as-warm-rolled statues, respectively.

Status	YS(MPa)	UTS(MPa)	EL(%)	Toughness(10⁴ MJ/m³)
C	192.8 ± 2.8	195.9 ± 5.8	0.5 ± 0.1	0.08 ± 0.03
WR	245.8 ± 22.6	395.2 ± 6.8	46.5 ± 5.7	1.56 ± 0.11

Fig. 2. (a) XRD profiles of the alloy. (b) Microstructure of the as-cast alloy. (c) Microstructure of the WR alloy. (d) Primary and secondary Zn phases.

Fig. 3. The WR alloy: (a) a representative T-EBSD measured microstructure colored according to the inverse pole figure (IPF), which is viewed normal to ND, i.e., IPF//ND. In the figure, subgrain and grain boundaries with misorientations larger than 5° and 15° are outlined in yellow and in black, respectively; (b) a map corresponding to (a), in which large, medium-sized, small and boundary grains are masked by yellow, light blue, light red and white, respectively; (c) {0001}, {-12-10}, and {-1100} pole figures of Zn grains.

Table 2 Grain size distribution in Fig. 3. Boundary grains have been excluded for statistics of small and medium-sized grains/subgrains in order to avoid distorted statistics. While boundary grains are included in statistics of large grains/subgrains since they are useful to estimate the least area of a large grain/subgrain. Criterion for an equiaxed grain is its aspect ratio (=length/width) ≤ 1.5. PCT and GOS stand for percentage and grain orientation spread, respectively.

Size	Small	Medium	Large
Equivalent diameter (μm)	<1	1-5	>5
Area (μm²)	<0.8	0.8-19.6	>19.6
Grains (PCT)	115 (74.7 %)	36 (23.4 %)	3 (1.9 %)
Grains with GOS ≤ 3° (PCT)	108 (93.9 %)	22 (61.1 %)	0 (0%)
Equiaxed grains (PCT)	62 (53.9 %)	20 (55.6 %)	0 (0%)
Subgrains (PCT)	268 (82.2 %)	58 (17.8 %)	0 (0%)

Fig. 4. TEM/HRTEM characterization of WR alloy: (a) bright field image of Zn grains; (b) intragranular network of fine LiZn4 precipitates; (c) HRTEM image of a β-LiZn 4 precipitate and its surrounding Zn matrix; (d) orientation relationship (OR) between the two phases deduced from fast Fourier transformed (FFT) diffraction patterns. In order to guide pattern indexing, calculated Zn pattern is illustrated with blue dots, while calculated β-LiZn 4 pattern is illustrated with red dots. For convenience, an index of Zn has no subscript, while that of β-LiZn 4 has a subscript of β.

Fig. 5. Corrosion morphologies and products of WR alloy after immersion in SBF until 30 days (a-h). (a1-h1) are areas enclosed by red squares in (a-h) observed at higher magnifications. Points 1-14 are selected for SEM/EDS analysis. (i) Typical morphologies of the corrosion products on the alloy surface. (f) Zn/O ratio of the uniform corrosion product layer. The kp values in Fig. 5(j) are parabolic rate constant calculated according to parabolic rate law, showing the variation rate of Zn/O ratio.

Table 3 Elemental composition of the selected points marked in Fig. 5.

		Element composition (at.%)
Sample	Point	C	O	P	Ca	Zn
WR alloy	1	13.73	5.93	-	-	80.34
	2	23.61	15.72			60.66
	3	34.92	6.90	1.96	0.48	55.73
	4	19.51	11.26	1.88	0.37	66.98
	5	19.90	22.47	4.58	1.94	51.11
	6	25.45	5.07	2.42	0.31	66.76
	7	23.56	32.96	2.3	0.67	40.5
	8	21	23.6	3.19	0.66	51.56
	9	16.66	57.62	6.61	2.43	16.68
	10	37.94	10.23			51.83
	11	25.43	19.83	3.71	1.32	49.71
	12	30.38	32.28	4.48	1.43	31.43
	13	9.03	58.68	11.42	6.65	14.23
	14	11.28	36.56	7.29	3.21	41.67

Fig. 6. SEM observations of the surface cross-section and corresponding linear EDS profiles of the WR alloy exposed to SBF for (a) 5 days, (b) 15 days and (c) 30 days. (d) Thicknesses of corrosion layer of the WR alloy after immersion in SBF.

Fig. 7. SEM observation of alloy surface morphology after the removal of corrosion products (a-h). (a1-h1) are enlarged areas marked by red squares in (a-h), revealing more details.

Fig. 8. Immersion in SBF: (a) alloy weight loss and corrosion rate (CRw); (b) Zn2+ release amount; (c) maximum (Max) depth of corrosion pits and CRp. The kp values in Fig. 8(a) and (b) are parabolic rate constant calculated according to parabolic rate law, showing the variation rate of fitted data.

Fig. 9. WR alloy immersed in SBF: (a) XPS spectra; (b) atomic concentration of elements detected by XPS; spectra of (c) Zn 2p and (d) Li 1?s regions.

Fig. 10. XPS spectrum of WR alloy after immersion in SBF for different days: narrow Zn 2p3/2 spectrum for (b) 1 day, (g) 15 days and (j) 30 days and narrow Li 1?s spectrums for (d) 1 day, (e) 5 days and (f) 15 days.

Table 4 Chemical identification obtained from XPS spectra of Li 1s and Zn 2p 3/2.

Element	Characterized bonds	Binding energy (eV)	References
Zn 2p_3/2	Zn	1020.8	[57]
	Zn(OH)₂	1021.8	[58]
	ZnO	1021.2	[59]
Li 1 s	LiCl	55.8	[60]
	LiOH	54.9	[60]
	Li₂CO₃	55.2	[60]

Fig. 11. (a) OCP values and (b) PDP curves of WR alloy immersed for different time; EIS of WR alloy immersed for different time: (c) Nyquist plots, (d) Bode plots of |Z| vs. frequency, (e) Bode plots of phase angle vs. frequency in SBF, (f) The equivalent circuit.

Table 5 Electrochemical parameters of WR alloy in SBF.

Time	β_a (mV/dec)	-β_c(mV/dec)	E_corr (V_SCE)	i_corr (μA/cm²)	R_LPR(kΩ cm²)	CR_LPR(mm/year)
1 day	-	244.02 ± 40.76	-1.06 ± 0.01	1.76 ± 0.19	60.32 ± 6.28	25.34 ± 2.27
3 days	-	206.34 ± 35.69	-1.07 ± 0.04	0.99 ± 0.16	90.52 ± 4.59	14.24 ± 1.16
5 days	-	135.32 ± 34.20	-1.08 ± 0.02	2.77 ± 0.14	21.22 ± 0.76	35.84 ± 5.66
7 days	66.31 ± 5.32	144.67 ± 21.24	-1.03 ± 0.01	4.62 ± 0.10	11.64 ± 2.47	66.04 ± 8.34
10 days	64.34 ± 1.21	168.23 ± 1.01	-0.98 ± 0.01	4.44 ± 0.39	10.16 ± 2.28	63.84 ± 9.55
15 days	63.02 ± 6.87	207.34 ± 35.15	-1.01 ± 0.01	8.13 ± 0.37	4.88 ± 1.03	115.18 ± 11.71
20 days	30.65 ± 6.04	74.70 ± 21.53	-0.94 ± 0.01	6.29 ± 0.72	3.64 ± 0.87	90.88 ± 16.19
30 days	40.33 ± 8.67	200.65 ± 15.11	-0.92 ± 0.01	10.04 ± 1.12	2.21 ± 0.80	142.92 ± 10.10

Table 6 Fitting parameters of WR alloy in SBF.

Time	R_s(Ω cm²)	CPE_dl(10^-5 Ω ^-1 cm^-2 sⁿ¹)	n	R_dl(kΩ cm²)	CPE₁(10^-7Ω^-1 cm^-2 sⁿ²)	n	R₁(kΩ cm²)	W (10^-5 Ω ^-1 cm^-2 s^0.5)	G (10^-5 Ω ^-1 cm^-2 s^0.5)	x² (10^-3)
1 day	7.5 ± 1.2	0.95 ± 0.20	0.83 ± 0.08	11.02 ± 0.65	11.37 ± 1.02	0.89 ± 0.02	5.16 ± 0.13	16.01 ± 2.84		7.70 ± 1.10
3 days	8.1 ± 1.3	0.74 ± 0.11	0.90 ± 0.05	21.42 ± 0.45	3.21 ± 0.20	0.84 ± 0.08	12.31 ± 0.77	8.72 ± 1.80		3.21 ± 0.53
5 days	6.1 ± 1.9	0.89 ± 0.07	0.92 ± 0.08	86.30 ± 0.87	0.10 ± 0.02	0.87 ± 0.05	17.44 ± 0.66	0.62 ± 0.11		4.62 ± 0.94
7 days	15.3 ± 2.2	8.01 ± 0.24	0.94 ± 0.04	3.92 ± 0.07	2.31 ± 1.44	0.89 ± 0.02	3.89 ± 0.43	47.04 ± 6.72		8.50 ± 1.42
10 days	14.1 ± 0.5	35.04 ± 3.70	0.69 ± 0.05	2.87 ± 0.04	2.94 ± 0.13	0.83 ± 0.07	3.29 ± 0.34		32.31 ± 1.74	0.85 ± 0.11
15 days	14.5 ± 1.2	22.24 ± 1.84	0.58 ± 0.02	1.58 ± 0.13	13.44 ± 0.51	0.73 ± 0.12	2.00 ± 0.09		17.12 ± 0.84	7.21 ± 1.62
20 days	20.6 ± 5.1	27.38 ± 3.22	0.53 ± 0.02	0.14 ± 0.09	95.47 ± 17.37	0.66 ± 0.08	1.29 ± 0.11		26.02 ± 1.53	7.83 ± 1.41
30 days	12.2 ± 0.6	88.17 ± 5.17	0.60 ± 0.04	0.69 ± 0.10	320 ± 30.22	0.54 ± 0.10	2.25 ± 0.06		75.01 ± 3.42	4.40 ± 1.33

Fig. 12. Values of toughness and immersion corrosion rate of biodegradable Zn and Zn alloys. Data are calculated from the literatures [[6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17],34,46,47,[63], [64], [65], [66], [67], [68], [69], [70], [71]] as well as in this work, which reported tensile strain-stress curves of Zn alloys and their immersion corrosion rates in SBF or Hank’s solution for around 30 days in the meantime.

Fig. 13. Schematic illustration of corrosion layers on the materials immersed in SBF solution.

References 79

[1]	J.H. Lee, E.D. Kim, E.J. Jun, H.S. Yoo, J.W. Lee, Biomater. Res. 22 (2018), 8-1-10.
[2]	H. Kitabata, R. Waksman, B. Warnack, Cardiovasc. Revasc. Med. 15 (2014) 109-116. DOI URL
[3]	E. Mostaed, M. Sikora-Jasinska, J.W. Drelich, M. Vedani, Acta Biomater. 71 (2018) 1-23. DOI PMID
[4]	P.K. Bowen, J. Drelich, J. Goldman, Adv. Mater. 25 (2013) 2577-2582. DOI URL
[5]	J. Venezuela, M.S. Dargusch, Acta Biomater. 87 (2019) 1-40. DOI PMID
[6]	Z.Z. Shi, J. Yu, X.F. Liu, Mater. Des. 144 (2018) 343-352. DOI URL
[7]	P. Li, C. Schille, E. Schweizer, F. Rupp, A. Heiss, C. Legner, U.E. Klotz, J. Geisgerstorfer, L. Scheideler, Int. J. Mol. Sci. 19 (2018) 755. DOI URL
[8]	M. Sikora-Jasinska, E. Mostaed, A. Mostaed, R. Beanland, D. Mantovani, M. Vedani, Mater. Sci. Eng. C 77 (2017) 1170-1181. DOI URL
[9]	S. Zhao, C.T. Mcnamara, P.K. Bowen, N. Verhun, J.P. Braykovich, J. Goldman, J.W. Drelich, Metall. Mater. Trans. A 48 (2017) 1204-1215. DOI URL
[10]	S. Zhao, J.M. Seitz, R. Eifler, H.J. Maier, R.J. Guillory, E.J. Earley, A. Drelich, J. Goldman, J.W. Drelich, Mater. Sci. Eng. C 76 (2017) 301-312. DOI URL
[11]	Y. Dai, Y. Zhang, H. Liu, H. Fang, D. Li, X. Xu, Y. Yan, L. Chen, Y. Lu, K. Yu, Mater. Lett. 235 (2019) 220-223. DOI URL
[12]	H.L. Jin, S. Zhao, R. Guillory, P.K. Bowen, Z.Y. Yin, A. Griebel, J. Schaffer, E.J. Earley, J. Goldman, J.W. Drelich, Mater. Sci. Eng. C 84 (2018) 67-79. DOI URL
[13]	E. Mostaed, M. Sikorajasinska, A. Mostaed, S. Loffredo, A.G. Demir, B. Previtali, D. Mantovani, R. Beanland, M. Vedani, J. Mech. Behav, Biomed. Mater. 60 (2016) 581-602.
[14]	C. Shen, X. Liu, B. Fan, P. Lan, F. Zhou, X. Li, H. Wang, X. Xiao, L. Li, S. Zhao, RSC Adv. 6 (2016) 86410-86419. DOI URL
[15]	H.F. Li, X.H. Xie, Y.F. Zheng, Y. Cong, F.Y. Zhou, K.J. Qiu, X. Wang, S.H. Chen, L. Huang, L. Tian, Sci. Rep. 5 (2015), 10719-1-13. DOI PMID
[16]	X. Tong, D. Zhang, X. Zhang, Y. Su, Z. Shi, K. Wang, J. Lin, Y. Li, J. Lin, C. Wen, Acta Biomater. 82 (2018) 197-204. DOI URL
[17]	Y. Zhang, Y. Yan, X. Xu, Y. Lu, L. Chen, D. Li, Y. Dai, Y. Kang, K. Yu, Mater. Sci. Eng. C 99 (2019) 1021-1034. DOI URL
[18]	Z. Li, Z.Z. Shi, Y. Hao, H.F. Li, X.F. Liu, A.A. Volinsky, H.J. Zhang, L.N. Wang, J. Mater. Sci, Technol. 35 (2019) 2618-2624.
[19]	Z. Li, Z.Z. Shi, Y. Hao, H.F. Li, H.J. Zhang, X.F. Liu, L.N. Wang, Mater. Sci. Eng. C 114 (2020), 111049.
[20]	D. Choudhuri, S. Meher, S. Nag, N. Dendge, J.Y. Hwang, R. Banerjee, Philos. Mag. Lett. 93 (2013) 395-404. DOI URL
[21]	J.F. Nie, B.C. Muddle, Acta Mater. 48 (2000) 1691-1703. DOI URL
[22]	M.X. Zhang, P.M. Kelly, Acta Mater. 53 (2005) 1073-1084. DOI URL
[23]	J. Yang, J.L. Wang, Y.M. Wu, L.M. Wang, H.J. Zhang, Mater. Sci. Eng.A 460-461 (2007) 296-300.
[24]	W.Z. Zhang, Z.P. Sun, J.Y. Zhang, Z.Z. Shi, H. Shi, J. Mater. Sci. 52 (2017) 4253-4264. DOI URL
[25]	X.P. Yang, W.Z. Zhang, Sci. China Technol. Sci. 55 (2012) 1343-1352. DOI URL
[26]	Q. Liang, W.T. Reynolds, Metall. Mater. Trans. A 29 (1998) 2059-2072. DOI URL
[27]	W.Z. Zhang, G.C. Weatherly, Prog. Mater. Sci. 50 (2005) 181-292. DOI URL
[28]	Z.Z. Shi, W.Z. Zhang, X.F. Gu, Philos. Mag. 92 (2012) 1071-1082. DOI URL
[29]	P.S. Guo, F.X. Li, L.J. Yang, R. Bagheri, Q.K. Zhang, B.Q. Li, K.L. Cho, Z.L. Song, W.S. Sun, H.N. Liu, Mater. Sci. Eng. A748 (2019) 262-266.
[30]	R.B. Figueiredo, T.G. Langdon, J. Mater. Sci. 45 (2010) 4827-4836. DOI URL
[31]	H. Zhang, H.Y. Wang, J.G. Wang, J. Rong, M. Zha, C. Wang, P.K. Ma, Q.C. Jiang, J. Alloys. Compd. 780 (2019) 312-317. DOI URL
[32]	M. Zha, H.M. Zhang, Z.Y. Yu, X.H. Zhang, X.T. Meng, H.Y. Wang, Q.C. Jiang, J. Mater. Sci. Technol. 34 (2018) 257-264. DOI URL
[33]	J. Venezuela, M.S. Dargusch, Acta Biomater. 87 (2019) 1-40. DOI PMID
[34]	H. Yang, B. Jia, Z. Zhang, X. Qu, G. Li, W. Lin, D. Zhu, K. Dai, Y. Zheng, Nat. Commun. 11 (2020) 401. DOI URL
[35]	S. Zhao, C.T. McNamara, P.K. Bowen, N. Verhun, J.P. Braykovich, J. Goldman, J.W. Drelich, Metall. Mater. Trans. A 48 (2017) 1204-1215. DOI URL
[36]	Z.Z. Shi, J. Yu, X.F. Liu, L.N. Wang, J. Mater. Sci. Technol. 34 (2018) 1008-1015. DOI URL
[37]	L. Liu, Y. Meng, A.A. Volinsky, H.J. Zhang, L.N. Wang, Corros. Sci. 153 (2019) 341-356. DOI URL
[38]	E. Mostaed, M. Sikora-Jasinska, A. Mostaed, S. Loffredo, A.G. Demir, B. Previtali, D. Mantovani, R. Beanland, M. Vedani, J. Mech. Behav. Biomed. 60 (2016) 581-602. DOI URL
[39]	J. Kubasek, D. Vojtech, E. Jablonska, I. Pospisilova, J. Lipov, T. Ruml, Mater. Sci. Eng. C 58 (2016) 24-35. DOI URL
[40]	H.F. Li, X.H. Xie, Y.F. Zheng, Y. Cong, F.Y. Zhou, K.J. Qiu, X. Wang, S.H. Chen, L. Huang, L. Tian, L. Qin, Sci. Rep. 5 (2015), 10719-1-14. DOI PMID
[41]	C. Shen, X. Liu, B. Fan, P. Lan, F. Zhou, X. Li, H. Wang, X. Xiao, L. Li, S. Zhao, Z. Guo, Z. Pu, Y. Zheng, RSC Adv. 6 (2016) 86410-86419. DOI URL
[42]	L. Wang, Y. He, H. Zhao, H. Xie, S. Li, Y. Ren, G. Qin, J. Alloys. Compd 740 (2018) 949-957. DOI URL
[43]	X. Liu, J. Sun, Y. Yang, F. Zhou, Z. Pu, L. Li, Y. Zheng, Mater. Lett. 162 (2016) 242-245. DOI URL
[44]	H. Li, H. Yang, Y. Zheng, F. Zhou, K. Qiu, X. Wang, Mater. Des. 83 (2015) 95-102. DOI URL
[45]	X. Liu, J. Sun, F. Zhou, Y. Yang, R. Chang, K. Qiu, Z. Pu, L. Li, Y. Zheng, Mater. Des. 94 (2016) 95-104. DOI URL
[46]	R. Yue, H. Huang, G. Ke, H. Zhang, J. Pei, G. Xue, G. Yuan, Mater. Charact. 134 (2017) 114-122. DOI URL
[47]	Z. Tang, H. Huang, J. Niu, L. Zhang, H. Zhang, J. Pei, J. Tan, G. Yuan, Mater. Des. 117 (2017) 84-94. DOI URL
[48]	P.K. Bowen, J.M. Seitz, R.J.Guillory 2nd, J.P. Braykovich, S. Zhao, J. Goldman, J.W. Drelich, J. Biomed. Mater. Res. 10 (2018) 245-258.
[49]	H.T. Chen, Z.Z. Shi, X.F. Liu, Mater. Sci. Eng. A 770 (2020), 138543. DOI URL
[50]	A.D. Pelton, J. Phase Equilib 12 (1991) 42-45. DOI URL
[51]	M.P. Bichat, J.L. Pascal, F. Gillot, F. Favier, Chem. Mater. 17 (2005) 6761-6771. DOI URL
[52]	Z.Z. Shi, J. Yu, Z.K. Ji, X.F. Liu, X.F. Gu, G. Han, J. Mater. Sci 54 (2018) 1728-1740. DOI URL
[53]	Z.Z. Shi, Y.D. Zhang, F. Wagner, T. Richeton, P.A. Juan, J.S. Lecomte, L. Capolungo, S. Berbenni, Acta Mater. 96 (2015) 333-343. DOI URL
[54]	S.W. Cheong, H. Weiland, Mater. Sci.Forum 558-559 (2007) 153-158.
[55]	Z.Z. Shi, Z.L. Li, W.S. Bai, A. Tuoliken, J. Yu, X.F. Liu, Mater. Des. 162 (2019) 235-245. DOI URL
[56]	Z. Gui, Z. Kang, Y. Li, J. Alloys. Compd 685 (2016) 222-230. DOI URL
[57]	D. Chadwick, T. Hashemi, Corros. Sci. 18 (1978) 39-51. DOI URL
[58]	P.M.G. Deroubaix, Surf. Interface Anal. 18 (1992) 39-46. DOI URL
[59]	B.R. Strohmeier, D.M. Hercules, J. Catal 86 (1984) 266-279. DOI URL
[60]	J.P. Contour, A. Salesse, M. Froment, M. Garreau, J. Thevenin, D. Warin, J. Microsc. Spectrosc. Electron. 4 (1979) 483-491.
[61]	L. Hou, M. Raveggi, X.B. Chen, W. Xu, K.J. Laws, Y. Wei, M. Ferry, N. Birbilis, J. Electrochem. Soc. 163 (2016) C324-C329. DOI URL
[62]	Y. Song, E.H. Han, D. Shan, C.D. Yim, B.S. You, Corros. Sci. 65 (2012) 322-330. DOI URL
[63]	M.S. Ardakani, E. Mostaed, M. Sikora-Jasinska, S.L. Kampe, J.W. Drelich, Mater. Sci. Eng. A 770 (2020), 138529.
[64]	M.S. Dambatta, S. Izman, D. Kurniawan, H. Hermawan, J. King Saud Univ. Sci. 29 (2017) 455-461. DOI URL
[65]	Z. Tang, J. Niu, H. Huang, H. Zhang, J. Pei, J. Ou, G. Yuan, J. Mech. Behav. Biomed. Mater. 72 (2017) 182-191. DOI URL
[66]	H.R. Bakhsheshi Rad, E. Hamzah, H.T. Low, M. Kasiri Asgarani, S. Farahany, E. Akbari, M.H. Cho, Mater. Sci. Eng. C 73 (2017) 215-219. DOI URL
[67]	C. Xiao, L. Wang, Y. Ren, S. Sun, E. Zhang, C. Yan, Q. Liu, X. Sun, F. Shou, J. Duan, H. Wang, G. Qin, . Mater. Sci. Technol. 34 (2018) 1618-1627.
[68]	M. W˛atroba, W. Bednarczyk, J. Kawałko, K. Mech, M. Marciszko, G. Boelter, M. Banzhaf, P. Bała, Mater. Des. 183 (2019), 108154. DOI URL
[69]	J. Lin, X. Tong, Z. Shi, D. Zhang, L. Zhang, K. Wang, A. Wei, L. Jin, J. Lin, Y. Li, C. Wen, Acta Biomater. 106 (2020) 410-427. DOI URL
[70]	L. Zhang, X.Y. Liu, H. Huang, W. Zhan, Mater. Lett. 244 (2019)119-122. DOI
[71]	R. Yue, J. Zhang, G. Ke, G. Jia, H. Huang, J. Pei, B. Kang, H. Zeng, G. Yuan, Mater. Sci. Eng. C 105 (2019), 110106. DOI URL
[72]	F. Zhang, J. Wang, T. Liu, C. Shang, Mater. Des. 186 (2020), 108330. DOI URL
[73]	Z. Lei, P. Gao, H. Li, Y. Cai, M. Zhan, Mater. Sci. Eng. A 753 (2019) 238-246. DOI URL
[74]	P.F. Gao, Z.N. Lei, X.X. Wang, M. Zhan, Mater. Sci. Eng. A 739 (2019) 198-202. DOI URL
[75]	Y. Song, D. Shan, R. Chen, E.H. Han, J. Alloys.Compd. 484 (2009) 585-590.
[76]	W. Wang, F. Mohammadi, A. Alfantazi, Corros. Sci. 57 (2012) 11-21. DOI URL
[77]	R.C. Zeng, L. Sun, Y.F. Zheng, H.Z. Cui, E.H. Han, Corros. Sci. 79 (2014) 69-82. DOI URL
[78]	L. Liu, Y. Meng, C.F. Dong, Y. Yan, A.A. Volinsky, L.N. Wang, J. Mater. Sci. Technol. 34 (2018) 2271-2282.
[79]	S.S. Zumdahl, Houghton Mifflin Company, 2009, pp. 23.