In Vitro Gradual Decrease in Strength of Ti Scaffolds in Hank’s Solution upon Long-Term Immersion: Challenges and Prospective Solutions

doi:10.1007/s40195-025-01867-5

Abstract

Abstract:

Although Ti scaffolds offer great potential in orthopedic applications, their porous nature raises new questions, such as low relative density and high surface area. This work investigated the gradual decrease in the strength of Ti scaffolds during long-term immersion in Hank’s solution. After 180-day immersion, the samples have a 23.3% and 26.6% reduction in yield strength and a 9.0% and 11.2% reduction in compressive strength in dynamic and static solutions, indicating potential failure during the long-term service. A large exposure area to the solution leads to a high corrosion rate, which results in the consumption of the scaffolds and, consequently, decreased strength. Although the covered deposits on the scaffolds reduce the ion release to some extent, the scaffolds still have a slowly ongoing decrease in strength. Based on the durability considerations, some methods, such as decreasing porosity and surface treatments, are proposed to alleviate this phenomenon of Ti scaffolds.

Key words: Laser powder bed fusion, Ti-6Al-4V, Corrosion, Porous scaffold, Strength

Yi-Fan Zhang, Liang-Yu Chen, Zi-Han Ge, Chenglong Teng, Yong Liu, Lai-Chang Zhang. In Vitro Gradual Decrease in Strength of Ti Scaffolds in Hank’s Solution upon Long-Term Immersion: Challenges and Prospective Solutions[J]. Acta Metallurgica Sinica (English Letters), 2025, 38(8): 1331-1339.

Figures/Tables 7

Fig. 1 Morphologies of LPBF-produced Ti-6Al-4V alloy scaffold used in this work: a an image of the scaffold with the indication of electrical discharge machining, and the inset is the digital model of the scaffold with rhombic dodecahedron cells, SEM images of b the as-built scaffold and c the sample after pickling, and d the enlarged view of the yellow dash rectangle in c

Fig. 2 Compressive properties of the samples before and after immersion: a yield strength, b compressive strength, c decreased fraction of the compressive strength, and d elastic modulus. OS indicates the sample before the immersion test. ST and DT illustrate that the samples were immersed in static and dynamic solutions

Fig. 3 Results of immersion tests: a weight gain and b morphologies of the immersed samples

Fig. 4 SEM analysis of the morphologies of the immersed samples after different durations: a ST60, b ST120, and c ST180; d-f the enlarged view of yellow dash rectangles in a-c; g DT60, h DT120, and i DT180; j-l the enlarged view of yellow dash rectangles in g-i

Table 1 EDS results of the point analysis of the dashed cycle in Fig. 4 (in wt%)

Spot	Ti	Al	V	O	Ca	P	K	Na	Cl
A	4.17	0.51	0.42	63.42	21.58	3.08	0.29	2.36	4.17
B	0.59	0.19	0.09	42.24	41.09	14.93	0.13	0.43	0.33
C	0.39	0.06	0.12	43.63	36.60	18.67	0.00	0.36	0.17
D	3.51	0.22	0.11	64.70	23.70	1.67	0.28	3.63	2.18
E	0.48	0.15	0.05	42.18	35.86	20.57	0.05	0.58	0.08
F	0.30	0.16	0.02	41.93	36.16	21.03	0.00	0.36	0.03

Fig. 5 Contents of released Ti, Al, and V ions in Hank's solution after three 60-day immersion periods

Fig. 6 Schematic illustration of long-term corrosion behavior of LPBF-produced Ti scaffolds in Hank's solution regarding the deposition, ion release, and substrate consumption: a commence of corrosion, b early stage of corrosion, c progress of corrosion, and d outcome of long-term corrosion

References 34

[1]	Y. L, D. Jiang, R. Zhu, C. Yang, L. Wang, L. C. Zhang, Int. J. Extrem. Manuf. 7, 022002 (2025)
[2]	Y.W. Cui, L. Wang, L.C. Zhang, Prog. Mater. Sci. 144, 101277 (2024)
[3]	L. Zhang, B. Song, S.K. Choi, Y. Shi, Int. J. Mech. Sci. 197, 106331 (2021)
[4]	N. Hafeez, J. Liu, L. Wang, D. Wei, Y. Tang, W. Lu, L.C. Zhang, Addit. Manuf. 34, 101264 (2020)
[5]	L.Y. Chen, S.X. Liang, Y. Liu, L.C. Zhang, Mater. Sci. Eng. R. Rep. 146, 100648 (2021)
[6]	H.Y. Ma, J.C. Wang, P. Qin, Y.J. Liu, L.Y. Chen, L.Q. Wang, L.C. Zhang, J. Mater. Sci. Technol. 183, 32 (2024)
[7]	L.Y. Chen, P. Qin, L. Zhang, L.C. Zhang, Int. J. Extrem. Manuf. 6, 052006 (2024)
[8]	Z. Jia, X. Xu, D. Zhu, Y. Zheng, Prog. Mater. Sci. 134, 101072 (2023)
[9]	Z.H. Ge, L.Y. Chen, Y.F. Zhang, Z.X. Wang, Y. Guo, C. Wu, D. Feng, C. Teng, Y. Liu, J. Manuf. Process. 133, 271 (2025)
[10]	P. Qin, L.Y. Chen, C.H. Zhao, Y.J. Liu, C.D. Cao, H. Sun, L.C. Zhang, Corros. Sci. 189, 109609 (2021)
[11]	H. Liu, Z.X. Wang, J. Cheng, N. Li, S.X. Liang, L. Zhang, F. Shang, D. Oleksandr, L.Y. Chen, J. Mater. Res. Technol. 27, 7882 (2023)
[12]	X. Gai, Y. Bai, S. Li, W. Hou, Y. Hao, X. Zhang, Y. Han, R. Yang, R.D.K. Misra, Corros. Sci. 181, 109258 (2021)
[13]	X. Chen, Q. Fu, Y. Jin, M. Li, R. Yang, X. Cui, M. Gong, Mater. Sci. Eng. C 70, 1071 (2017)
[14]	Y. Yang, F. Li, J. Ren, L. Zhang, X. Wang, Z. Li, Y. Jiang, Z. He, Vacuum 215, 112353 (2023)
[15]	C. Guerra, M. Sancy, M. Walczak, C. Martínez, A. Ringuedé, M. Cassir, J. Han, K. Ogle, H.G. de Melo, V. Salinas, C. Aguilar, Mater. Sci. Eng. C 111, 110758 (2020)
[16]	W. Abd-Elaziem, M.A. Darwish, A. Hamada, W.M. Daoush, Mater. Des. 241, 112850 (2024)
[17]	M. Heywood, Z. Shi, Y. Li, C. Wen, J. Kanwar, Y. Xiao, A. Atrens, Mater. Corros. 70, 529 (2019)
[18]	L.Y. Chen, H.Y. Zhang, C. Zheng, H.Y. Yang, P. Qin, C. Zhao, S. Lu, S.X. Liang, L. Chai, L.C. Zhang, Mater. Des. 208, 109907 (2021)
[19]	Y. Xu, L. Liu, C. Xu, X. Wang, M.Y. Tan, Y. Huang, Solid State Electrochem. 24, 2511 (2020)
[20]	Y.J. Liu, S.J. Li, L.C. Zhang, Y.L. Hao, T.B. Sercombe, Scr. Mater. 153, 99 (2018)
[21]	Y.F. Zhang, L.Y. Chen, Y. Liu, H.Y. Yang, J.H. Peng, C. Zheng, L. Zhang, L.C. Zhang, J. Mater. Res. Technol. 34, 1933 (2025)
[22]	J. Wang, R. Zhu, Y. Liu, L. Zhang, Adv. Powder Mater. 2, 100137 (2023)
[23]	Y. Xu, M.Y. Tan, Corros. Sci. 151, 163 (2019)
[24]	C.I. David, G. Prabakaran, R. Nandhakumar, Microchem. J. 169, 106590 (2021)
[25]	Y.H. Chu, L.Y. Chen, B.Y. Qin, W. Gao, F. Shang, H.Y. Yang, L. Zhang, P. Qin, L.C. Zhang, Acta Metall. Sin.-Engl. Lett. 37, 102 (2024)
[26]	W.Y. Ching, P. Rulis, A. Misra, Acta Biomater. 5, 3067 (2009) DOI PMID
[27]	J. Li, H. Zhong, B. Cao, Z. Ran, J. Tan, L. Deng, Y. Hao, J. Yan, Acta Metall. Sin.-Engl. Lett. 37, 54 (2024)
[28]	S. Lee, S. Yang, I. Bajpai, I.K. Kang, S. Kim, Acta Metall. Sin.-Engl. Lett. 28, 1109 (2015)
[29]	A. Mombelli, D. Hashim, N. Cionca, Clin. Oral Implant Res. 29, 37 (2018)
[30]	D. Xiao, J. Zhang, C. Zhang, D. Barbieri, H. Yuan, L. Moroni, G. Feng, Acta Biomater. 106, 22 (2020)
[31]	M.P. Nikolova, M.D. Apostolova, Materials 16, 183 (2023)
[32]	L.Y. Chen, Y.W. Cui, L.C. Zhang, Metals 10, 1139 (2020)
[33]	Z. Yan, S. Zhang, L. Ren, X. Bai, K. Yang, X. Wei, Acta Metall. Sin.-Engl. Lett. 37, 1767 (2024)
[34]	I. Cvijović-Alagić, S. Laketić, M. Momčilović, J. Ciganović, J. Bajat, V. Kojić, Acta Metall. Sin.-Engl. Lett. 37, 1215 (2024)