Effects of Electropolishing on Mechanical Properties and Bio-Corrosion of Ti6Al4V Fabricated by Electron Beam Melting Additive Manufacturing
Abstract
1. Introduction
2. Material and Methods
3. Results and Discussions
3.1. Powder Analysis
3.2. Surface Roughness
3.3. Surface Morphology
3.4. Surface Compositions Analysis
3.5. Mechanical Response
3.6. Bio-Corrosion Electrochemical Response
3.7. Closing Remarks
4. Conclusions
- (1)
- The current spherical, smooth and non-broken shape of Ti6Al4V powders can result in good powder flow and uniform powder bed during EBM. But the as-EBMed surface would contain partially melted powders, forming a rougher surface with Ra ~ 24 μm.
- (2)
- The electropolishing treatment is able to achieve surface improvement from Ra over ~24 μm down to about 4.5 μm with proper EP solution, voltage, current density, temperature and duration time.
- (3)
- Via the proper EP, the stress concentration effect can be pronouncedly reduced, upgrading the subsequent tensile performance to raise the UTS by 6% and tensile elongation by 53%. With decreasing Ra values, the mechanical response is continuously upgraded in this study.
- (4)
- According to potentiodynamic polarization results, the as-EBMed sample with the highest Ra possesses the higher Ecorr, Icorr and Ipass values. With decreasing Ra, the bio-corrosion rate becomes much lower.
- (5)
- However, when the EP treatment is over-done, the tiny dots induced by EP would impose some negative effects on the bio-corrosion in SBF. Proper EP treatments should result in a flatter surface without tiny EP-induced defects.
Author Contributions
Funding
Conflicts of Interest
References
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Ra (µm) | Kt | Young’s Modulus (GPa) | Yield Stress (MPa) | Ultimate Tensile Stress (MPa) | Tensile Elongation (%) | |
---|---|---|---|---|---|---|
Unpolished | 24.1 ± 2.6 | 2.8 ± 0.3 | 100 ± 2 | 813 ± 3 | 995 ± 8 | 7.6 ± 0.4 |
Polished 1 | 15.1 ± 1.2 | 2.4 ± 0.1 | 103 ± 2 | 817 ± 2 | 1012 ± 13 | 8.7 ± 0.5 |
Polished 2 | 10.2 ± 0.9 | 2.0 ± 0.2 | 100 ± 1 | 809 ± 5 | 1025 ± 7 | 9.3 ± 0.4 |
Polished 3 | 4.5 ± 0.5 | 1.2 ± 0.1 | 102 ± 3 | 817 ± 2 | 1052 ± 8 | 11.6 ± 0.7 |
Ra (µm) | OCP E (V) | Ecorr (V) | Epit (V) | ΔE (V) | Icorr (nA/cm2) | Ipass (µA/cm2) |
---|---|---|---|---|---|---|
24.1 ± 2.6 | −0.25 | −0.270 ± 0.014 | 1.850 ± 0.034 | >2 | 54.36 ± 7.80 | 6.71 ± 0.16 |
19.0 ± 0.7 | −0.38 | −0.413 ± 0.007 | >2 | >2 | 29.38 ± 8.28 | 2.80 ± 0.08 |
15.1 ± 1.2 | −0.45 | −0.394 ± 0.025 | >2 | >2 | 22.19 ± 1.97 | 2.88 ± 0.06 |
10.2 ± 1.3 | −0.32 | −0.369 ± 0.008 | >2 | >2 | 15.47 ± 4.40 | 2.68 ± 0.42 |
4.5 ± 0.8 | −0.23 | −0.225 ± 0.020 | >2 | >2 | 27.24 ± 5.89 | 2.90 ± 0.32 |
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Wu, Y.-C.; Kuo, C.-N.; Chung, Y.-C.; Ng, C.-H.; Huang, J.C. Effects of Electropolishing on Mechanical Properties and Bio-Corrosion of Ti6Al4V Fabricated by Electron Beam Melting Additive Manufacturing. Materials 2019, 12, 1466. https://doi.org/10.3390/ma12091466
Wu Y-C, Kuo C-N, Chung Y-C, Ng C-H, Huang JC. Effects of Electropolishing on Mechanical Properties and Bio-Corrosion of Ti6Al4V Fabricated by Electron Beam Melting Additive Manufacturing. Materials. 2019; 12(9):1466. https://doi.org/10.3390/ma12091466
Chicago/Turabian StyleWu, Yao-Cheng, Che-Nan Kuo, Yueh-Chun Chung, Chee-How Ng, and Jacob C. Huang. 2019. "Effects of Electropolishing on Mechanical Properties and Bio-Corrosion of Ti6Al4V Fabricated by Electron Beam Melting Additive Manufacturing" Materials 12, no. 9: 1466. https://doi.org/10.3390/ma12091466
APA StyleWu, Y.-C., Kuo, C.-N., Chung, Y.-C., Ng, C.-H., & Huang, J. C. (2019). Effects of Electropolishing on Mechanical Properties and Bio-Corrosion of Ti6Al4V Fabricated by Electron Beam Melting Additive Manufacturing. Materials, 12(9), 1466. https://doi.org/10.3390/ma12091466