Research Papers

Investigation and Optimization of Laser Welding of Ti-6Al-4 V Titanium Alloy Plates

[+] Author and Article Information
Fabrizia Caiazzo

e-mail: f.caiazzo@unisa.it

Vittorio Alfieri

e-mail: valfieri@unisa.it

Gaetano Corrado

e-mail: gcorrado@unisa.it

Francesco Cardaropoli

e-mail: fcardaro@unisa.it

Vincenzo Sergi

e-mail: sergi@unisa.it

Department of Industrial Engineering,
University of Salerno,
Fisciano, Salerno 84084, Italy

Manuscript received March 28, 2013; final manuscript received September 25, 2013; published online November 18, 2013. Assoc. Editor: Yung Shin.

J. Manuf. Sci. Eng 135(6), 061012 (Nov 18, 2013) (8 pages) Paper No: MANU-13-1111; doi: 10.1115/1.4025578 History: Received March 28, 2013; Revised September 25, 2013

Titanium alloys are employed in a wide range of applications, from aerospace to medicine. In particular, Ti-6Al-4 V is the most common, thanks to an excellent combination of low density, high specific strength, and corrosion resistance. Laser welding has been increasingly considered as an alternative to traditional techniques to join titanium alloys. An increase in penetration depth and a reduction of possible welding defects are indeed achieved; moreover, a smaller grain size in the fused zone (FZ) is benefited in comparison to either tungsten inert gas (TIG) or plasma arc welding, thus improving the tensile strength of the welded structures. This study was carried out on 3 mm thick Ti-6Al-4 V plates in square butt welding configuration. The novelty element of the investigation is the use of a disk-laser source, which allows a number of benefits thanks to better beam quality; furthermore, a proper device was developed for bead protection, as titanium is prone to oxidation when in fused state. A three-level factorial plan was arranged in face-centered cubic scheme. The regression models were found for a number of crucial responses and the corresponding surfaces were discussed; then a numerical optimization was carried out. The suggested condition was evaluated to compare the actual responses to the predicted values; X-ray inspections, Vickers micro hardness tests, and tensile tests were performed for the optimum.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.


Donachie, M. J., 2000, Titanium, A Technical Guide, ASM International, Materials Park, OH.
Cao, X., and Jahazi, M., 2009, “Effect of Welding Speed on Butt Joint Quality of Ti-6Al-4V Alloy Welded Using a High-Power Nd:YAG Laser,” Opt. Laser Eng., 47(11), pp. 1231–1241. [CrossRef]
Cardaropoli, F., Alfieri, V., Caiazzo, F., and Sergi, V., 2012, “Manufacturing of Porous Biomaterials for Dental Implant Applications Through Selective Laser Melting,” Adv. Mater. Res., 535–537, pp. 1222–1229. [CrossRef]
Tsay, L. W., and Tsay, C. Y., 1997, “The Effect of Microstructures on the Fatigue Crack Growth in Ti-6Al-4V Laser Welds,” Int. J. Fatigue, 19(10), pp. 713–720. [CrossRef]
Sun, Z., Pan, D., and Zhang, W., 2002, “Correlation Between Welding Parameters and Microstructures in TIG, Plasma and Laser Welded Ti-6Al-4V,” 6th International Conference on Trends in Welding Research, Pine Mountain, pp. 760–767.
Haapala, K. R., Zhao, F., Camelio, J., Sutherland, J. W., Skerlos, S. J., Dornfeld, D. A., Jawahir, I. S., Clarens, A. F., and Rickli, J. L., 2013, “A Review of Engineering Research in Sustainable Manufacturing,” ASME J. Manuf. Sci. Eng., 135(4), p. 041013. [CrossRef]
Marimuthu, S., Eghlio, R. M., Pinkerton, A. J., and Li, L., 2013, “Coupled Computational Fluid Dynamic and Finite Element Multiphase Modeling of Laser Weld Bead Geometry Formation and Joint Strengths,” ASME J. Manuf. Sci. Eng., 135(1), p. 011004. [CrossRef]
Wang, S., and Wu, X., 2012, “Investigation on the Microstructure and Mechanical Properties of Ti-6Al-4V Alloy Joints With Electron Beam Welding,” Mater. Des., 36, pp. 663–670. [CrossRef]
Mazumder, J., and Steen, W. M., 1980, “Welding of Ti-6Al-4V by Continuous Wave CO2 Laser,” Met. Constr., 12(9), pp. 423–427.
Caiazzo, F., Curcio, F., Daurelio, G., and Memola Capece Minutolo, F., 2004, “Ti6Al4V Sheets Lap and Butt Joints Carried out by CO2 Laser: Mechanical and Morphological Characterization,” J. Mater. Process. Technol., 149, pp. 546–552. [CrossRef]
Akman, E., Demir, A., Canel, T., and Sinmazcelik, T., 2009, “Laser Welding of Ti6Al4V Titanium Alloys,” J. Mater. Process. Technol., 209(8), pp. 3705–3713. [CrossRef]
Kabir, A. S. H., Cao, X., Medraj, M., Wanjara, P., Cuddy, J., and Birur, A., 2010, “Effect of Welding Speed and Defocusing Distance on the Quality of Laser Welded Ti–6Al–4V,” Proceedings of the Materials Science and Technology (MS&T) 2010 Conference, Houston, TX, pp. 2787–2797.
Liu, H., Nakata, K., Yamamoto, N., and Liao, J., 2012, “Microstructural Characteristics and Mechanical Properties in Laser Beam Welds of Ti6Al4V Alloy,” J. Mater. Sci., 47(3), pp. 1460–1470. [CrossRef]
Mastrocinque, E., Corrado, G., Caiazzo, F., Pasquino, N., Sergi, V., and Acerra, F., 2011, “Disk Laser Welding of Ti6Al4V Alloy,” 21st International Conference on Production Research, Stuttgart.
Caiazzo, F., Mastrocinque, E., Corrado, G., and Sergi, V., 2012, “Regression Modeling to Predict the Geometrical Features of Ti6Al4V Thin Sheets Butt Joints Welded by Disk Laser,” Proceedings of SPIE Photonics Europe 2012, Bruxelles, Vol. 8433, Paper No. 84330Y1-11.
Giesen, A., and Speiser, J., 2007, “Fifteen Years of Work on Thin-Disk Lasers: Results and Scaling Laws,” J. Sel. Top. Quantum Electron., 13(3), pp. 598–609. [CrossRef]
Steen, W. M., 2003, Laser Material Processing, Springer, London, pp. 157–199.
Duley, W. W., 1998, Laser Welding, John Wiley and Sons, Inc., New York.
Mastrocinque, E., Corrado, G., Caiazzo, F., Pasquino, N., and Sergi, V., 2012, “Effect of Defocusing on Bead-on-Plate of Ti6Al4V by Yb:YAG Disk Laser,” Adv. Mater. Res., 383–390, pp. 6258–6264. [CrossRef]
Montgomery, D. C., 2005, Design and Analysis of Experiment, McGraw-Hill, New York.
Anderson, M. J., and Whitcomb, P. J., 2000, DOE Simplified: Practical Tools for Effective Experimentation, Productivity Press, Portland, OR.
AWS, 2001, Specification for Fusion Welding for Aerospace Applications, American Welding Society, Miami, FL.
Alfieri, V., Cardaropoli, F., Caiazzo, F., and Sergi, V., 2011, “Porosity Evolution in Aluminum Alloy 2024 BOP and Butt Defocused Welding by Yb:YAG Disk Laser,” Eng. Rev., 31(2), pp. 125–132.
Caiazzo, F., Sergi, V., Corrado, G., Alfieri, V., and Cardaropoli, F., 2012, “Apparato Automatizzato di Saldatura Laser,” Patent No. SA2012 A,000,016.
Ahmed, T., and Rack, H., 1998, “Phase Transformation During Cooling in α + β Titanium Alloys,” Mater. Sci. Eng., A243, pp. 206–211. [CrossRef]
Caiazzo, F., Alfieri, V., Cardaropoli, F., and Sergi, V., 2012, “Butt Autogenous Laser Welding of AA 2024 Aluminium Alloy Thin Sheets With a Yb:YAG Disk Laser,” Int. J. Adv. Manuf. Technol., 67, pp. 2157–2169. [CrossRef]
Ruggiero, A., Tricarico, L., Olabi, A. G., and Benyounis, K. Y., 2011, “Weld-Bead Profile and Costs Optimisation of the CO2 Dissimilar Laser Welding Process of Low Carbon Steel and Austenitic Steel AISI316,” Opt. Laser Technol., 43, pp. 82–90 [CrossRef].
ASTM, 2004, “Standard Test Methods for Tension Testing of Metallic Materials,” ASTM International, West Conshohocken, PA, Standard No. E8M-04 [CrossRef].
British Standard, 2011, “Destructive Tests on Welds in Metallic Materials—Hardness Test: Part 2—Micro Hardness Testing on Welded Joints,” BSI, London, Standard No. EN ISO 9015-2.
Gao, X., Zhang, L., Liu, J., and Zhang, J., 2013, “A Comparative Study of Pulsed Nd:YAG Laser Welding and TIG Welding of Thin Ti6Al4V Titanium Alloy Plate,” Mater. Sci. Eng. A, 559, pp. 14–21. [CrossRef]


Grahic Jump Location
Fig. 2

Bead characterization: geometric features (above) and imperfections (below)

Grahic Jump Location
Fig. 1

Face-centered central composite design scheme

Grahic Jump Location
Fig. 4

Bead aspect of the specimen corresponding to the center point of the experimental plan

Grahic Jump Location
Fig. 5

Cross-section micrograph of the specimen corresponding to the center point of the plan

Grahic Jump Location
Fig. 6

Micrograph of the base metal

Grahic Jump Location
Fig. 7

Micrograph of the heat affected zone for the specimen corresponding to the center point of the plan

Grahic Jump Location
Fig. 8

Micrograph of the fused zone (center point of the plan)

Grahic Jump Location
Fig. 15

X-ray transmitted image of the bead as obtained in the suggested optimal welding condition

Grahic Jump Location
Fig. 16

Vickers micro hardness trend in the cross-section

Grahic Jump Location
Fig. 9

Fused zone as a function of thermal input

Grahic Jump Location
Fig. 10

Fused zone as a function of power

Grahic Jump Location
Fig. 11

Fused zone as a function of welding speed

Grahic Jump Location
Fig. 12

Bead profile with a focused (left) and defocused beam (right), all other parameters being equal

Grahic Jump Location
Fig. 13

(a) Shape factor for a given speed of 20 mm/s and (b) shape factor for a given negative focus position of 3 mm

Grahic Jump Location
Fig. 14

(a) Grain size for a given power of 2000 W and (b) grain size for a given speed of 20 mm/s

Grahic Jump Location
Fig. 17

Fracture surfaces from tensile tests, top-side (left), back-side (right)




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In