Journal of Materials Science

, Volume 55, Issue 4, pp 1715–1726 | Cite as

On the potential mechanisms of β to α′ + β decomposition in two phase titanium alloys during additive manufacturing: a combined transmission Kikuchi diffraction and 3D atom probe study

  • Niyanth SridharanEmail author
  • Yimeng Chen
  • Peeyush Nandwana
  • Robert M. Ulfig
  • David J. Larson
  • Sudarsanam Suresh Babu
Metals & corrosion


This paper focuses on the mechanisms of phase transformations in additively manufactured Ti–6Al–4V during cooling. In particular, the goal is to understand if the imposed thermal cycles during fabrication results in the complete transformation of the α′ to the β phase or the sub-transus decomposition of α′ (martensite) to α + β. To this effect, samples fabricated using electron beam melting and laser-directed energy deposition techniques were analyzed using atom probe tomography (APT) in conjunction with correlative transmission Kikuchi diffraction (TKD). While the composition measurement using APT shows partitioning of vanadium into the β phase, the crystallographic analysis suggests evidence of a shear-induced transformation. Despite the pronounced differences in the processing conditions, both of the additive manufacturing techniques lead to similar partitioning of vanadium to the β phase. Calculations using THERMOCALC and DICTRA show that under the time and temperature regimes of additive manufacturing the microstructure could develop by the decomposition reaction of α’ → α+β.



The sample fabrication via additive manufacturing was supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office, under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The lead author would like to acknowledge the Laboratory Directed Research and Development program at Oak Ridge National Laboratory for financial support, and the Applications Development Group at CAMECA Instruments Inc. for hardware and engineering support for EIKOS-X.

Compliance with ethical standards

Conflict of interest

The authors with a CAMECA affiliation acknowledge a financial conflict of interest with respect to the topic of this paper. The other authors declare that they have no conflict of interests.


  1. 1.
    Tarzimoghadam Z, Sandlöbes S, Pradeep KG, Raabe D (2015) Microstructure design and mechanical properties in a near-α Ti–4Mo alloy. Acta Mater 97:291–304CrossRefGoogle Scholar
  2. 2.
    Banerjee R, Collins PC, Bhattacharyya D, Banerjee S, Fraser HL (2003) Microstructural evolution in laser deposited compositionally graded α/β titanium–vanadium alloys. Acta Mater 51:3277–3292CrossRefGoogle Scholar
  3. 3.
    Banerjee R, Bhattacharyya D, Collins PC, Viswanathan GB, Fraser HL (2004) Precipitation of grain boundary α in a laser deposited compositionally graded Ti–8Al–xV alloy—an orientation microscopy study. Acta Mater 52:377–385CrossRefGoogle Scholar
  4. 4.
    Bhattacharyya D, Viswanathan GB, Denkenberger R, Furrer D, Fraser HL (2003) The role of crystallographic and geometrical relationships between α and β phases in an α/β titanium alloy. Acta Mater 51:4679–4691CrossRefGoogle Scholar
  5. 5.
    Kelly SM, Babu SS, David SA, Zacharia T, Kampe SL (2005) A microstructure model for laser processing of Ti–6Al–4V. In: Proceedings of international conference in trends in welding research, pp 65–70Google Scholar
  6. 6.
    Makiewicz KT (2013) Development of simultaneous transformation kinetics microstructure model with application to laser metal deposited Ti–6Al–4V and alloy 718. The Ohio State UniversityGoogle Scholar
  7. 7.
    Lütjering G, Williams JC (2007) Titanium. Springer, BerlinGoogle Scholar
  8. 8.
    Gu DD, Meiners W, Wissenbach K, Poprawe R (2012) Laser additive manufacturing of metallic components: materials, processes and mechanisms. Int Mater Rev 57:133–164. CrossRefGoogle Scholar
  9. 9.
    Sames WJ, List FA, Pannala S, Dehoff RR, Babu SS (2016) The metallurgy and processing science of metal additive manufacturing. Int Mater Rev 61:315–360CrossRefGoogle Scholar
  10. 10.
    Kelly SM (2004) Thermal and microstructure modeling of metal deposition processes with application to Ti–6Al–4 VGoogle Scholar
  11. 11.
    Kelly SM, Kampe SL (2004) Microstructural evolution in laser-deposited multilayer Ti–6Al–4V builds: Part II. Thermal modeling. Metall Mater Trans 35:1869–1879CrossRefGoogle Scholar
  12. 12.
    Antonysamy AA, Meyer J, Prangnell PB (2013) Effect of build geometry on the β-grain structure and texture in additive manufacture of Ti 6Al 4V by selective electron beam melting. Mater Charact 84:153–168CrossRefGoogle Scholar
  13. 13.
    Wang F, Williams S, Colegrove P, Antonysamy AA (2013) Microstructure and mechanical properties of wire and arc additive manufactured Ti–6Al–4 V. Metall Mater Trans A 44:968–977CrossRefGoogle Scholar
  14. 14.
    Sridharan N, Chaudhary A, Nandwana P, Babu SS (2016) Texture evolution during laser direct metal deposition of Ti–6Al–4 V. JOM 68:968–977. CrossRefGoogle Scholar
  15. 15.
    Antonysamy AA (2012) Microstructure, texture and mechanical property evolution during additive manufacturing of Ti6Al4V alloy for aerospace applications. School of MaterialsGoogle Scholar
  16. 16.
    Xu W, Lui EW, Pateras A, Qian M, Brandt M (2017) In situ tailoring microstructure in additively manufactured Ti–6Al–4V for superior mechanical performance. Acta Mater 125:390–400CrossRefGoogle Scholar
  17. 17.
    Xu W, Brandt M, Sun S, Elambasseril J, Liu Q, Latham K, Xia K, Qian M (2015) Additive manufacturing of strong and ductile Ti–6Al–4V by selective laser melting via in situ martensite decomposition. Acta Mater 85:74–84CrossRefGoogle Scholar
  18. 18.
    Tan X, Kok Y, Toh WQ, Tan YJ, Descoins M, Mangelinck D, Tor SB, Leong KF, Chua CK (2016) Revealing martensitic transformation and α/β interface evolution in electron beam melting three-dimensional-printed Ti–6Al–4 V. Sci Rep 6:26039–26049CrossRefGoogle Scholar
  19. 19.
    Kelly SM, Kampe SL (2004) Microstructural evolution in laser-deposited multilayer Ti–6Al–4V builds: Part I. Microstructural characterization. Metall Mater Trans 35:1861–1867CrossRefGoogle Scholar
  20. 20.
    Elmer JW, Palmer TA, Babu SS, Zhang W, DebRoy T (2004) Phase transformation dynamics during welding of Ti–6Al–4 V. J Appl Phys 95:8327–8339CrossRefGoogle Scholar
  21. 21.
    Elmer JW, Palmer TA, Wong J (2003) In situ observations of phase transitions in Ti–6Al–4V alloy welds using spatially resolved x-ray diffraction. J Appl Phys 93:1941–1947CrossRefGoogle Scholar
  22. 22.
    Tan X, Kok Y, Tan YJ, Descoins M, Mangelinck D, Tor SB, Leong KF, Chua CK (2015) Graded microstructure and mechanical properties of additive manufactured Ti–6Al–4V via electron beam melting. Acta Mater 97:1–16CrossRefGoogle Scholar
  23. 23.
    Al-Bermani SS, Blackmore ML, Zhang W, Todd I (2010) The origin of microstructural diversity, texture, and mechanical properties in electron beam melted Ti–6Al–4 V. Metall Mater Trans A 41:3422–3434. CrossRefGoogle Scholar
  24. 24.
    Sridharan N, Gussev M, Seibert R, Parish C, Norfolk M, Terrani K, Babu SS (2016) Rationalization of anisotropic mechanical properties of Al-6061 fabricated using ultrasonic additive manufacturing. Acta Mater. CrossRefGoogle Scholar
  25. 25.
    Kelly SM, Kampe SL (2004) Microstructural evolution in laser-deposited multilayer Ti–6Al–4V builds: Part II. Thermal modeling. Metall Mater Trans A 35:1869–1879CrossRefGoogle Scholar
  26. 26.
    Al-Bermani SS, Blackmore ML, Zhang W, Todd I (2010) The origin of microstructural diversity, texture, and mechanical properties in electron beam melted Ti–6Al–4V. Metall Mater Trans A 41:3422–3434CrossRefGoogle Scholar
  27. 27.
    Thompson K, Lawrence D, Larson DJ, Olson JD, Kelly TF, Gorman B (2007) In situ site-specific specimen preparation for atom probe tomography. Ultramicroscopy. CrossRefGoogle Scholar
  28. 28.
    Larson DJ, Foord DT, Petford-Long AK, Cerezo A, Smith GDW (1999) Focused ion-beam specimen preparation for atom probe field-ion microscopy characterization of multilayer film structures. Nanotechnology. CrossRefGoogle Scholar
  29. 29.
    Larson DJ, Ulfig RM, Lenz DR, Bunton JH, Shepard JD, Payne TR, Rice KP, Chen Y, Prosa TJ, Rauls DJ, Kelly TF, Sridharan N, Babu S (2018) Microstructural investigations in metals using atom probe tomography with a novel specimen-electrode geometry. JOM. CrossRefGoogle Scholar
  30. 30.
    Lee E, Banerjee R, Kar S, Bhattacharyya D, Fraser HL (2007) Selection of α variants during microstructural evolution in α/β titanium alloys. Philos Mag 87:3615–3627CrossRefGoogle Scholar
  31. 31.
    Haubrich J, Gussone J, Barriobero-Vila P, Kürnsteiner P, Jägle EA, Raabe D, Schell N, Requena G (2019) The role of lattice defects, element partitioning and intrinsic heat effects on the microstructure in selective laser melted Ti–6Al–4V. Acta Mater. CrossRefGoogle Scholar
  32. 32.
    Hellman OC, Vandenbroucke JA, Rüsing J, Isheim D, Seidman DN (2000) Analysis of three-dimensional atom-probe data by the proximity histogram. Microsc Microanal 6:437–444CrossRefGoogle Scholar
  33. 33.
    Martin TL, Radecka A, Sun L, Simm T, Dye D, Perkins K, Gault B, Moody MP, Bagot PAJ (2016) Insights into microstructural interfaces in aerospace alloys characterised by atom probe tomography. Mater Sci Technol 32:232–241. CrossRefGoogle Scholar
  34. 34.
    Hellman OC, Rüsing J, Sebastian JT, Seidman DN (2001) Atom-by-atom chemistry of internal interfaces: simulations and experiments. Mater Sci Eng, C 15:13–15CrossRefGoogle Scholar
  35. 35.
    Yan M, Dargusch MS, Ebel T, Qian M (2014) A transmission electron microscopy and three-dimensional atom probe study of the oxygen-induced fine microstructural features in as-sintered Ti–6Al–4V and their impacts on ductility. Acta Mater 68:196–206. CrossRefGoogle Scholar
  36. 36.
    Wang SC, Aindow M, Starink MJ (2003) Effect of self-accommodation on α/α boundary populations in pure titanium. Acta Mater 51:2485–2503CrossRefGoogle Scholar
  37. 37.
    Shi R, Dixit V, Fraser HL, Wang Y (2014) Variant selection of grain boundary α by special prior β grain boundaries in titanium alloys. Acta Mater 75:156–166CrossRefGoogle Scholar
  38. 38.
    Shi R, Dixit V, Viswanathan GB, Fraser HL, Wang Y (2016) Experimental assessment of variant selection rules for grain boundary α in titanium alloys. Acta Mater 102:197–211CrossRefGoogle Scholar
  39. 39.
    Shi R (2014) Variant selection during alpha precipitation in titanium alloys: a simulation study. The Ohio State UniversityGoogle Scholar
  40. 40.
    Babu SS, Kelly SM, Specht ED, Palmer TA, Elmer JW (2005) Measurement of phase transformation kinetics during repeated thermal cycling of Ti–6Al–4V using time-resolved X-ray diffraction. In: International conference on solid-solid phase transformations in inorganic materials 2005, pp 503–508Google Scholar
  41. 41.
    Yan M, Xu W, Dargusch MS, Tang HP, Brandt M, Qian M (2014) Review of effect of oxygen on room temperature ductility of titanium and titanium alloys. Powder Metall 57:251–257. CrossRefGoogle Scholar
  42. 42.
    Aziz MJ (1982) Model for solute redistribution during rapid solidification. J Appl Phys. CrossRefGoogle Scholar
  43. 43.
    Bhadeshia H, David SA, Vitek JM (1991) Solidification sequences in stainless steel dissimilar alloy welds. Mater Sci Technol 7:50–61CrossRefGoogle Scholar
  44. 44.
    Liu Z, Welsch G (1988) Literature survey on diffusivities of oxygen, aluminum, and vanadium in alpha titanium, beta titanium, and in rutile. Metall Trans A. CrossRefGoogle Scholar

Copyright information

© This is a U.S. government work and its text is not subject to copyright protection in the United States; however, its text may be subject to foreign copyright protection 2019

Authors and Affiliations

  1. 1.Material Science and Technology DivisionOak Ridge National LaboratoryOak RidgeUSA
  2. 2.University of TennesseeKnoxvilleUSA
  3. 3.CAMECA Instruments Inc.MadisonUSA
  4. 4.Energy Science and Transportation DivisionOak Ridge National LaboratoryOak RidgeUSA

Personalised recommendations