MICROSTRUCTURE, HARDNESS AND SURFACE ROUGHNESS CHARACTERIZATION OF EBM FABRICATED Ti-6Al-4V SAMPLES

Authors

1 Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran

2 Department of Applied Science and Technology, Politecnico Di Torino, Torino24, 10129, Italy

Abstract

Electron beam melting (EBM) is among the modern additive manufacturing processes whereby metal powders are selectively melted to produce very complicated components with superior mechanical properties. In this study, microstructure, hardness, and surface roughness of EBM fabricated Ti6Al4V samples were characterized. The results showed that the microstructure consisted of epitaxially-grown primary columnar β phase transformed to basketweave and Widmanstatten-type α phase during the subsequent rapid cooling. Martensitic needle-type α phase was also observed on the surfaces of the specimens. It was shown that higher parts of the sample had finer microstructures than the lower parts reaching to less than 340 nm in average thickness of the α layers due to distancing from the hot build platform rendering less opportunity for diffusional β → α+β transformation. The porosity content of the samples was lower than that of some other additive manufacturing processes. Vickers micro-hardness of the samples was measured to be around 337 HV which was higher than those reported for other additive manufacturing processes of the alloy.

Keywords

References

1. Liu, K., and Lin, H., “A Study on the Relationship Between Technical Development and Fundamental Patents Based on US Granted Patents”, European International Journal of Science and Technology, Vol. 3, pp. 317-318, 2014.‌
2. Gibson, I., David, W., and Stucker, R.B., “Additive Manufacturing Technologies”, Rapid Prototyping to Direct Digital Manufacturing, Vol. 54, pp. 17-25, 2010.
3. https://www.ge.com/additive/
4. Samy, A., and Anandaraj, A., Microstructure, Texture and Mechanical Property Evolution During Additive Manufacturing of Ti6Al4V Alloy for Aerospace Applications, The University of Manchester, United Kingdom, 2012.
5. Sepe, R., Franchitti, S., Borrelli, R., Dicaprio, F., Armentani, E., and Caputo, F., “Correlation Between Real Geometry and Tensile Mechanical Behaviour for Ti6Al4V Electron Beam Melted Thin Specimens”, Theoretical and Applied Fracture Mechanics, Vol. 107, pp. 1-5, 2020.
6. Murr, L. E., Gaytan, S. M., Ceylan, A., Martinez, E., Martinez, J. L., Hernandez, D. H., and Wicker, R. B., “Characterization of Titanium Aluminide Alloy Components Fabricated by Additive Manufacturing Using Electron Beam Melting”, Acta Materialia, Vol. 58, pp.1-8, ‌2010.
7. Chern, A. H., Nandwana, P., Yuan, T., Kirka, M. M., Dehoff, R. R., Liaw, P. K., and Duty, C. E., “A Review on the Fatigue Behavior of Ti-6Al-4V Fabricated by Electron Beam Melting Additive Manufacturing”, International Journal of Fatigue, Vol. 119, pp. 173-184, 2019.‌
8. Wang, H., Warnken, N, and Reed, R.C., "Thermodynamic and Kinetic Modeling of Bcc Phase in the Ti–Al–V Ternary System", Materials Science and Engineering: A, Vol. 528.2, PP. 622-630. 2010.
9. Galarraga, H., Warren, R. J., Lados, D. A., Dehoff, R. R., Kirka, M. M., and Nandwana, P., “Effects of Heat Treatments on Microstructure and Properties of Ti-6Al-4V ELI Alloy Fabricated by Electron Beam Melting (EBM)”, Materials Science and Engineering, Vol. 685, pp. 2-26, 2017.
10. Ahmed, T., and Rack, H. J., “Phase Transformations During Cooling in [α]+[β] Titanium Alloys”, Materials Science and Engineering A, Vol. 243(1-2): pp. 206-211, 1998.
11. Bhattacharyya, D., Viswanathan, G. B., Denkenberger, R., Furrer D., and Fraser, H.L., “The Role of Crystallographic and Geometrical Relationships Between α and β Phases in an α-β Titanium Alloy”, Acta Materialia, Vol. 51(16), pp. 1-13, 2003.
12. Donachie, M.J. Titanium: a Technical Guide. ASM international, 2000.
13. Rafi, H. K., "Microstructures and Mechanical Properties of Ti6Al4V Parts Fabricated by Selective Laser Melting and Electron Beam Melting", Journal of Materials Engineering and Performance, Vol. 22(12), pp. 22-12, 2013.
14. Razavi S. M. J., Van Hooreweder B., and Berto F., “Effect of Build Thickness and Geometry on Quasi-Static and Fatigue Behavior of Ti-6Al-4V Produced by Electron Beam Melting”, Additive Manufacturing, Vol. 36, 101426, 2020.‌
15. Pushilina, N. S., Stepanova, E. N., Kudiiarov, V. N., Laptev, R. S., and Syrtanov, M. S., “Heat Treatment of the Ti-6Al-4V Alloy Manufactured by Electron Beam Melting”, AIP Conference Proceedings, Vol. 2167, pp. 020290, 2019.
16. Popov, V., Katz-Demyanetz, A., Garkun, A., Muller, G., Strokin, E., and Rosenson, H., “Effect of Hot Isostatic Pressure Treatment on the Electron-Beam Melted Ti-6Al-4V Specimens”, Procedia Manufacturing, Vol. 21, pp.125-132, 2018.‌
17. Liu, Z., Wang, Z., Gao, C., Liu, R., and Xiao, Z., “Microstructure, Anisotropic Mechanical Properties and Very High Cycle Fatigue Behavior of Ti6Al4V Produced by Selective Electron Beam Melting“, Metals and Materials International, pp. 1-12, 2020.
18. Dharmendra, C., Alaghmandfard, R., Hadadzadeh, A., Amirkhiz, B. S., and Mohammadi, M., “Influence of Build Orientation on Small-Scale Properties of Electron Beam Melted Ti-6Al-4V”, Materials Letters, Vol. 266, pp. 1-6, 2020.‌
19. Liu, S., and Shin, Y. C., “Additive Manufacturing of Ti6Al4V Alloy: A Review”, Materials & Design, Vol. 164, pp. 107552, 2019.
20. Raghavan, S., Nai, M. L. S., Wang, P., Sin, W. J., Li, T., and Wei, J.,” Heat Treatment of Electron Beam Melted (EBM) Ti-6Al-4V: Microstructure to Mechanical Property Correlations”, Rapid Prototyping Journal, Vol. 24, pp. 774-7832018
21. Galarraga, H., Lados, D.A., Dehoff, R.R., Kirka, M.M., and Nandwana P., “Effects of the Microstructure and Porosity on Properties of Ti-6Al-4V ELI Alloy Fabricated by Electron Beam Melting (EBM)”, Additive Manufacturing, Vol. 10, pp. 1-11, 2016.
22. Suzuki, M., Ousaka, Y., Nakamura, J., Sugimoto, T., and Ohtori, S.,” Wear Characteristics of Carbon Nanotube Reinforced Titanium Alloys”, Chiba Medical Journal, Vol.92(6), pp.43-48, 2016.‌
23. Nicoletto, G., Konečná, R., Frkáň, M., and Riva, E., “Surface Roughness and Directional Fatigue Behavior of As-Built EBM and DMLS Ti6Al4V”, International Journal of Fatigue, Vol. 116, pp. 140-148, 2018.
Journal of Advanced Materials in Engineering (Esteghlal)
Volume 40, Issue 4
March 2022
Pages 51-67

Files

Share

How to cite

Statistics

ارتقاء امنیت وب با وف ایرانی