Abstract
Friction stir welding (FSW) has been refined to create butt welds from two sheets of Ti-6Al-4V alloy to have an ultra-fine grain size. Weld specimen testing was completed for three different FSW process conditions: As welded, stress relieved, stress relieved and machined, and for the un-welded base material. The investigation includes macrostructure, microstructure, microhardness, tensile property testing, notched bar impact testing, and fracture toughness evaluations. All experiments were conducted in accordance with industry standard testing specifications. The microstructure in the weld nugget was found to consist of refined and distorted grains of alpha in a matrix of transformed beta containing acicular alpha. The enhanced fracture toughness of the welds is a result of increased hardness, which is attributed to an increase in alpha phase, increase in transformed beta in acicular alpha, and grain refinement during the weld process. The noted general trend in mechanical properties from as welded, to stress relieved, to stress relieved and machined conditions exhibited a decrease in ultimate tensile strength, and yield strength with a small increase in ductility and a significant increase in fracture toughness.
Similar content being viewed by others
References
R.S. Mishra and M.W. Mahoney: Friction Stir Welding and Processing, ed. (Materials Park, OH: ASM International, 2007).
T.J. Lienert: Friction Stir Welding and Processing, ed. (Materials Park, OH: ASM International, 2007), pp. 123–154.
P.D. Edwards and M. Ramulu, Sci. Technol. Weld. Join. 14, 775 (2009).
R. Nandan, T. DebRoy, and H.K.D.H. Bhadeshia, Prog. Mater Sci. 53, 980 (2008).
D. Sanders, P. Edwards, G. Grant, M. Ramulu, and A.P. Reynolds, EuroSPF (France: Carcassonne, 2008).
R.S. Mishra and Z.Y. Ma, Mater. Sci. Eng. R 50, 1 (2005).
Y. Shang, Y.S. Sato, H. Kokawa, S.H.C. Park, and S. Hirano, Mater. Sci. Eng. A 488, 25 (2008).
W.B. Lee, C.Y. Lee, W.S. Chang, Y.M. Yeon, and S.B. Jung, Mater. Lett. 59, 3315 (2005).
A.L. Pilchak, M.C. Juhas, and J.C. Williams, Metall. Mater. Trans. 38A, 401 (2007).
A.L. Pilchak, D.M. Norfleet, M.C. Juhas, and J.C. Williams: Metall. Mater. Trans. 39A, 1519 (2008).
S. Mironov, Y. Zhang, and Y.S. Sato, H. Kokawa. Scripta Mater. 59, 27 (2008).
S. Mironov, Y. Zhang, and Y.S. Sato, H. Kokawa. Scripta Mater. 59, 511 (2008).
A. Lauro, Weld. Int. 26, 8 (2012).
S. Pasta and A.P. Reynolds, Fatigue Fract. Eng. Mater. Struct. 31, 569 (2008).
Y. Zhang, Y.S. Sato, H. Kokawa, S.H.C. Park, and S. Hirano, Mater. Sci. Eng. A 485, 448 (2008).
L. Zhou, H.J. Liu, and Q.W. Liu, J. Mater. Sci. (Netherlands) 45, 39 (2010).
L. Zhou, H.J. Liu, and Q.W. Liu, Mater. Des. 31, 2631 (2010).
H.J. Liu, L. Zhou, and Q.W. Liu, Mater. Des. 31, 1650 (2010).
H. Liu, K. Nakata, N. Yamamoto, and J. Liao, Sci. Technol. Weld. Join. 15, 428 (2010).
P.D. Edwards and M. Ramulu, Int. J. Fatigue 70, 171 (2015).
D.G. Sanders, M. Ramulu, E.J. Klock-McCook, P.D. Edwards, A.P. Reynolds, T. Trapp: AeroMat Conference, International Symposium on Superplasticity and Superplastic Forming (SPF), Baltimore, MD 2007
D.G. Sanders: 2007, Development of Friction Stir Welding Combined with Superplastic Forming Processes for the Fabrication of Titanium Structures. PhD Dissertation, University of Washington, Seattle, WA.
E.J. Klock-McCook: Characterization of Friction Stir Welded and Superplasticly Formed Friction Stir Welded Joints of Titanium. Masters Thesis, University of Washington, Seattle, WA.
P.D. Edwards: Experimental and Numerical Characterization of Friction Stir Welded and Superplastically Formed—Friction Stir Welded Titanium. Masters Thesis, University of Washington, Seattle, WA.
M. Ramulu, P. Labossiere, and T. Greenwell, Opt. Lasers Eng. 48, 385 (2010).
M. Ramulu, P. Labossioure, and T. Greenwell, Appl. Mech. Mater. 692, 490 (2014).
P.D. Edwards and M. Ramulu, J. Eng. Mater. Technol. 132, 0310061 (2010).
P.D. Edwards, D.G. Sanders, and M. Ramulu, J. Mater. Eng. Perform. 19, 510 (2010).
D.G. Sanders, M. Ramulu, P.D. Edwards, and A. Cantrell, J. Mater. Eng. Perform. 19, 503 (2010).
P.D. Edwards, D.G. Sanders, M. Ramulu, G. Grant, T. Trapp, and P. Comley, J. Mater. Eng. Perform. 19, 481 (2010).
P. Edwards, M. Ramulu, and D. Sanders, Key Eng. Mater. 433, 169 (2010).
G.D. Sanders and M. Ramulu, Mater. Sci. Forum 735, 395 (2013).
R.W. Fonda and K.E. Knipling, Acta Mater. 58, 6452 (2010).
N. Kulkarni and M. Ramulu: Proceedings of the ASME2014 International Mechanical Engineering Congress & Exposition (IMECE2014), Montreal, 2014, Paper # IMECE2014-39211.
M.J. Donachie, Jr.: Titanium and Titanium Alloys ed. (Materials Park, OH: American Society for Metals, 1982).
Material Property Data, March, 2009, http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MTP641.
Acknowledgements
The University of Washington acknowledges the support and cooperation of the Boeing Company during the course of this study.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sanders, D.G., Edwards, P., Cantrell, A.M. et al. Friction Stir-Welded Titanium Alloy Ti-6Al-4V: Microstructure, Mechanical and Fracture Properties. JOM 67, 1054–1063 (2015). https://doi.org/10.1007/s11837-015-1376-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11837-015-1376-x