Microstructure and mechanical properties of a Ti6Al4V alloy recycled by waste chips vacuum arc melting

Dilara Nur Ozkan; Omer Sahin; Kursat Icin; Volkan Kilicli; Neset Akar

doi:10.1515/mt-2023-0296

Article

Microstructure and mechanical properties of a Ti6Al4V alloy recycled by waste chips vacuum arc melting

Dilara Nur Ozkan
Ms. Dilara Nur Ozkan was born in 1995, study at the Department of Metallurgical and Materials Engineering, Gazi University, Ankara, Turkey. He received his BSc degree from Department of Metallurgical and Materials Engineering, Kırıkkale University in 2017. He received his MSc degree from Department of Metallurgical and Materials Engineering, Gazi University in 2023. His research interests include recycling of metals and alloys, materials characterization, and mechanical tests.
, Omer Sahin
Mr. Omer Sahin was born in 1988, works at the Department of Metallurgical and Materials Engineering, Gazi University, Ankara, Turkey. He received his BSc and MSc degrees from Department of Metallurgical and Materials Engineering, Karadeniz Technical University in 2015 and 2018, respectively. His research interests include heat treatments of steels and cast irons, materials characterization, and mechanical tests.
, Kursat Icin
Assist Prof. Dr. Kursat Icin was born in 1990, works at the Department of Metallurgical and Materials Engineering, Karadeniz Technical University, Trabzon, Turkey. He received his BSc degrees from Department of Metallurgical and Materials Engineering, Karadeniz Technical University in 2013. He received his MSc and PhD degrees from Karadeniz Technical University in 2016 and 2022, respectively. His areas of interest include NdFeB hard magnets, high-entropy alloy, and vacuum arc melting.
, Volkan Kilicli
Assoc. Prof. Dr. Volkan Kilicli was born in 1980, works at the Department of Metallurgical and Materials Engineering, Faculty of Technology, Gazi University, Ankara, Turkey. He graduated from Department of Metallurgy Education from Gazi University in 2001. He received his MSc and PhD degrees from Gazi University in 2004 and 2010, respectively. His research interests include heat treatments of steels and cast irons, semi-solid processing of aluminum alloys, self-healing metallic materials, and metal matrix composites.
and Neset Akar
Assoc. Prof. Dr. Neset Akar was born in 1973, works at the Department of Metallurgical and Materials Engineering, Faculty of Technology, Gazi University, Ankara, Turkey. He graduated from Department of Metallurgy Education from Gazi University in 1996. He received his MSc and PhD degrees from Gazi University in 2000 and 2006, respectively. His research interests are and casting technologies, computer aided casting design, and semi-solid processing of aluminum alloys.

Published/Copyright: March 20, 2024

Published by

Become an author with De Gruyter Brill

Submit Manuscript Author Information

From the journal Materials Testing Volume 66 Issue 5

Abstract

This study investigated the microstructure and mechanical properties of the recycled Ti6Al4V alloy produced using the waste chips vacuum arc melting (VAM) process. The waste chips were cleaned to remove machining residues before VAM and dried in the oven. The dried and compressed chip compacts are vacuum arc melted and hot rolled. Microstructural characterization was performed by using an optical microscope, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analysis. Mechanical properties were determined by tensile and hardness tests. The microstructures of recycled Ti6Al4V alloy, which produced the VAM process, consist of acicular structures due to rapid solidification. After hot rolling from 950 °C, the elongated α grains and transformed β grains consisting of fine acicular α phase were observed. The recycled Ti6Al4V alloy by hot rolling after VAM exhibited very low total elongation compared to the as-received Ti6Al4V alloy. While a micro dimples ductile fracture was observed on the fracture surfaces of the as-received Ti6Al4V alloy after the tensile test, a brittle fracture surface was observed in the recycled Ti6Al4V alloy samples after VAM + hot rolling due to the coarse α and β grain structure after cooling in the air after hot rolling.

Keywords: Ti6Al4V alloy; waste chip; recycling; vacuum arc melting (VAM); mechanical properties

Corresponding author: Neset Akar, Department of Metallurgical and Materials Engineering, Gazi University Faculty of Technology, Ankara 06560, Türkiye, E-mail: nakar@gazi.edu.tr

About the authors

Dilara Nur Ozkan

Ms. Dilara Nur Ozkan was born in 1995, study at the Department of Metallurgical and Materials Engineering, Gazi University, Ankara, Turkey. He received his BSc degree from Department of Metallurgical and Materials Engineering, Kırıkkale University in 2017. He received his MSc degree from Department of Metallurgical and Materials Engineering, Gazi University in 2023. His research interests include recycling of metals and alloys, materials characterization, and mechanical tests.

Omer Sahin

Mr. Omer Sahin was born in 1988, works at the Department of Metallurgical and Materials Engineering, Gazi University, Ankara, Turkey. He received his BSc and MSc degrees from Department of Metallurgical and Materials Engineering, Karadeniz Technical University in 2015 and 2018, respectively. His research interests include heat treatments of steels and cast irons, materials characterization, and mechanical tests.

Kursat Icin

Assist Prof. Dr. Kursat Icin was born in 1990, works at the Department of Metallurgical and Materials Engineering, Karadeniz Technical University, Trabzon, Turkey. He received his BSc degrees from Department of Metallurgical and Materials Engineering, Karadeniz Technical University in 2013. He received his MSc and PhD degrees from Karadeniz Technical University in 2016 and 2022, respectively. His areas of interest include NdFeB hard magnets, high-entropy alloy, and vacuum arc melting.

Volkan Kilicli

Assoc. Prof. Dr. Volkan Kilicli was born in 1980, works at the Department of Metallurgical and Materials Engineering, Faculty of Technology, Gazi University, Ankara, Turkey. He graduated from Department of Metallurgy Education from Gazi University in 2001. He received his MSc and PhD degrees from Gazi University in 2004 and 2010, respectively. His research interests include heat treatments of steels and cast irons, semi-solid processing of aluminum alloys, self-healing metallic materials, and metal matrix composites.

Neset Akar

Assoc. Prof. Dr. Neset Akar was born in 1973, works at the Department of Metallurgical and Materials Engineering, Faculty of Technology, Gazi University, Ankara, Turkey. He graduated from Department of Metallurgy Education from Gazi University in 1996. He received his MSc and PhD degrees from Gazi University in 2000 and 2006, respectively. His research interests are and casting technologies, computer aided casting design, and semi-solid processing of aluminum alloys.

Acknowledgment

The authors would like to thank Prof. Dr. Sultan Öztürk from the Department of Metallurgical and Materials Engineering, KTU, who provided to produce samples by vacuum arc melting, and Research Assistant Sefa Emre Sünbül from the Department of Metallurgical and Materials Engineering, Gaziantep University.

Research ethics: The authors declare that no AI writing tools were used in this paper.
Author contributions: The author(s) have accepted responsibility for the entire content of this manuscript and approved its submission. Dilara Nur Ozkan: Experimental studies (waste material supply and processing), paper writing. Omer Sahin: Experimental studies (microstructural characterization and mechanical testing), paper writing. Kursat Icin: Experimental studies (vacuum arc melting), paper writing. Volkan Kilicli: Paper writing, figures creating and editing, and reviewing. Neset Akar: Conceptualization, experimental studies (rolling), paper writing.
Competing interests: The authors states no conflict of interest.
Research funding: None declared.
Data availability: The raw data can be obtained on request from the corresponding author.

References

[1] D. Banerjee and J. C. Williams, “Perspectives on titanium science and technology,” Acta Mater., vol. 61, no. 1, pp. 844–879, 2013, https://doi.org/10.1016/j.actamat.2012.10.043.Search in Google Scholar

[2] R. R. Boyer, “An overview on the use of titanium in the aerospace industry,” Mater. Sci. Eng. A, vol. 213, nos. 1–2, pp. 102–114, 1996, https://doi.org/10.1016/0921-5093(96)10233-1.Search in Google Scholar

[3] H. Sibum, “Titanium and titanium alloys-from raw material to semi-finished products,” Adv. Eng. Mater., vol. 5, no. 6, pp. 393–398, 2003, https://doi.org/10.1002/adem.200310092.Search in Google Scholar

[4] M. Yamada, “An overview on the development of titanium alloys for non-aerospace application in Japan,” Mater. Sci. Eng. A, vol. 213, nos. 1–2, pp. 8–15, 1996, https://doi.org/10.1016/0921-5093(96)10241-0.Search in Google Scholar

[5] E. Ünal and H. Yalçın, “Finite element method analysis of a linear friction welded Ti6Al4V alloy,” Mater. Test., vol. 65, no. 6, pp. 886–895, 2023, https://doi.org/10.1515/mt-2022-0337.Search in Google Scholar

[6] S. Önder and N. Saklakoğlu, “Selective laser melting of Ti6Al4V alloy: effects of process parameters at constant energy density on mechanical properties, residual stress, microstructure and relative density,” Mater. Test., vol. 65, no. 2, pp. 162–173, 2023, https://doi.org/10.1515/mt-2022-0240.Search in Google Scholar

[7] K. Beyl, K. Mutombo, and C. Kloppers, “Tensile properties and microstructural characterization of additive manufactured, investment cast and wrought Ti6Al4V alloy,” IOP Conf. Ser. Mater. Sci. Eng., vol. 655, no. 1, 2019, Art. no. 012023, https://doi.org/10.1088/1757-899X/655/1/012023.Search in Google Scholar

[8] A. Festas, R. Pereira, A. Ramos, and J. Davim, “A study of the effect of conventional drilling and helical milling in surface quality in titanium Ti-6Al-4V and Ti-6AL-7Nb alloys for medical applications,” Arab. J. Sci. Eng., vol. 46, no. 3, pp. 2361–2369, 2021, https://doi.org/10.1007/s13369-020-05047-8.Search in Google Scholar

[9] P. Luo, H. Xie, M. Paladugu, S. Palanisamy, M. S. Dargusch, and K. Xia, “Recycling of titanium machining chips by severe plastic deformation consolidation,” J. Mater. Sci., vol. 45, no. 17, pp. 4606–4612, 2010. https://doi.org/10.1007/s10853-010-4443-2.Search in Google Scholar

[10] D. McDonald, E. W. Lui, S. Palanisamy, M. S. Dargusch, and K. Xia, “Achieving superior strength and ductility in Ti-6Al-4V recycled from machining chips by equal channel angular pressing,” Metall. Mater. Trans. A, vol. 45, pp. 4089–4102, 2014, https://doi.org/10.1007/s11661-014-2323-0.Search in Google Scholar

[11] K. Topolski, W. Bochniak, M. Łagoda, P. Ostachowski, and H. Garbacz, “Structure and properties of titanium produced by a new method of chip recycling,” J. Mater. Process. Technol., vol. 248, pp. 80–91, 2017, https://doi.org/10.1016/j.jmatprotec.2017.05.005.Search in Google Scholar

[12] O. Takeda and T. H. Okabe, “Current status of titanium recycling and related technologies,” JOM, vol. 71, no. 6, pp. 1981–1990, 2018, https://doi.org/10.1007/s11837-018-3278-1.Search in Google Scholar

[13] O. Takeda, T. Ouchi, and T. H. Okabe, “Recent progress in titanium extraction and recycling,” Metall. Mater. Trans. B, vol. 51, no. 4, pp. 1315–1328, 2020. https://doi.org/10.1007/s11663-020-01898-6.Search in Google Scholar

[14] L. Bian, S. M. Thompson, and N. Shamsaei, “Mechanical properties and microstructural features of direct laser-deposited Ti-6Al-4V,” JOM, vol. 67, no. 3, pp. 629–638, 2015. https://doi.org/10.1007/s11837-015-1308-9.Search in Google Scholar

[15] C. Pirozzi, S. Franchitti, R. Borrelli, G. Diodati, and G. Vattasso, “Experimental study on the porosity of electron beam melting-manufactured Ti6Al4V,” J. Mater. Eng. Perform., vol. 28, no. 5, pp. 2649–2660, 2019. https://doi.org/10.1007/s11665-019-04038-7.Search in Google Scholar

[16] M. Gökelma, D. Celik, O. Tazegul, H. Cimenoglu, and B. Friedrich, “Characteristics of Ti6AL4V powders recycled from turnings via the HDH technique,” Metals, vol. 8, no. 5, pp. 336–346, 2018, https://doi.org/10.3390/met8050336.Search in Google Scholar

[17] J. Umeda, T. Mimoto, H. Imai, and K. Kondoh, “Powder forming process from machined titanium chips via heat treatment in hydrogen atmosphere,” Mater. Trans., vol. 58, no. 12, pp. 1702–1707, 2017, https://doi.org/10.2320/matertrans.Y-M2017833.Search in Google Scholar

[18] R. Atwood, P. Lee, R. Minisandram, and R. F. Jones, “Multiscale modelling of microstructure formation during vacuum arc remelting of titanium 6-4,” J. Mater. Sci., vol. 39, no. 24, pp. 7193–7197, 2004. https://doi.org/10.1023/B:JMSC.0000048731.42495.1c.10.1023/B:JMSC.0000048731.42495.1cSearch in Google Scholar

[19] ASTM E1447-22, Standard Test Method for Determination of Hydrogen in Reactive Metals and Reactive Metal Alloys by Inert Gas Fusion with Detection by Thermal Conductivity or Infrared Spectrometry, West Conshohocken, PA, USA. ASTM International, Jun. 2022 [Online]. Available at: https://www.astm.org/e1447-22.html.Search in Google Scholar

[20] ASTM E8/8M-22, Standard Test Methods for Tension Testing of Metallic Materials, West Conshohocken, PA, USA. ASTM International, Jul. 2022 [Online]. Available at: https://www.astm.org/e0008_e0008m-22.html.Search in Google Scholar

[21] E. W. Lui, S. Palanisamy, M. S. Dargusch, and K. Xia, “Effects of chip conditions on the solid state recycling of Ti-6Al-4V machining chips,” J. Mater. Process. Technol., vol. 238, pp. 297–304, 2016, https://doi.org/10.1016/j.jmatprotec.2016.07.028.Search in Google Scholar

[22] W. Hofmeister and M. Griffith, “Solidification in direct metal deposition by LENS processing,” JOM, vol. 53, no. 9, pp. 30–34, 2001. https://doi.org/10.1007/s11837-001-0066-z.Search in Google Scholar

[23] S. Bontha, N. W. Klingbeil, P. A. Kobryn, and H. L. Fraser, “Thermal process maps for predicting solidification microstructure in laser fabrication of thin-wall structures,” J. Mater. Process. Technol., vol. 178, nos. 1–3, pp. 135–142, 2006, https://doi.org/10.1016/j.jmatprotec.2006.03.155.Search in Google Scholar

[24] J. Alcisto, et al., “Tensile properties and microstructures of laser-formed Ti-6Al-4V,” J. Mater. Eng. Perform., vol. 20, no. 2, pp. 203–102, 2010. https://doi.org/10.1007/s11665-010-9670-9.Search in Google Scholar

[25] R. R. Boyer, “Titanium and titanium alloys,” in ASM Handbook:Metallography and Microstructures, vol. 9, G. F. Vander Voort, Ed., OH, USA, ASM International, 2004, pp. 458–475.Search in Google Scholar

[26] G. Welsch, R. Boyer, and E. Collings, Materials Properties Handbook: Titanium Alloys, 1st ed., OH, USA, ASM International, 1993.Search in Google Scholar

[27] M. N. Doğu, Z. Esen, K. Davut, E. Tan, B. Gümüş, and A. F. Dericioglu, “Microstructural and texture evolution during thermo-hydrogen processing of Ti6Al4V alloys produced by electron beam melting,” Mater. Charact., vol. 168, 2020, Art. no. 110549, https://doi.org/10.1016/j.matchar.2020.110549.Search in Google Scholar

[28] ASTM B367-22, Standard Specification for Titanium and Titanium Alloy Castings, West Conshohocken, PA, USA. ASTM International, Apr. 2022 [Online]. Available at: https://www.astm.org/b0367-22.html.Search in Google Scholar

[29] ASTM F1472-23, Standard Specification for Wrought Titanium-6 Aluminium-4 Vanadium Alloy for Surgical Implant Applications (UNS R56400), West Conshohocken, PA, USA. ASTM International, Feb. 2023 [Online]. Available at: https://www.astm.org/f1472-23.html.Search in Google Scholar

[30] S. Tamirisakandala, R. Bhat, and B. Vedam, “Recent advances in the deformation processing of titanium alloys,” J. Mater. Eng. Perform., vol. 12, no. 6, pp. 661–673, 2003. https://doi.org/10.1361/105994903322692466.Search in Google Scholar

[31] K. Fan, et al., “Effect of residual stress induced by ultrasonic surface rolling on fretting fatigue behaviors of Ti-6Al-4V alloy,” Eng. Fract. Mech., vol. 259, pp. 1–12, 2022. https://doi.org/10.1016/j.engfracmech.2021.108150.Search in Google Scholar

[32] A.-W. El-Morsy, “Microstructural characterization of Ti–6Al–4V machining chips after remelting and severe deformation,” Mater. Des., vol. 30, no. 5, pp. 1825–1829, 2009, https://doi.org/10.1016/j.matdes.2008.07.029.Search in Google Scholar

[33] M. Simonelli, Y. Y. Tse, and C. Tuck, “Effect of the build orientation on the mechanical properties and fracture modes of SLM Ti–6Al–4V,” Mater. Sci. Eng., A, vol. 616, pp. 1–11, 2014, https://doi.org/10.1016/j.msea.2014.07.086.Search in Google Scholar

Published Online: 2024-03-20

Published in Print: 2024-05-27

You are currently not able to access this content.

Articles in the same Issue

https://doi.org/10.1515/mt-2023-0296

Keywords for this article

Ti6Al4V alloy; waste chip; recycling; vacuum arc melting (VAM); mechanical properties