Surface transformation hardening of Ti-5Al-2.5Sn alloy by pulsed Nd:YAG laser: an experimental study

  • Ali KhorramEmail author
  • Akbar Davoodi Jamaloei
  • Abed Jafari


In this study, surface hardening of Ti-5Al-2.5Sn alloy was performed using a pulsed Nd:YAG laser. The effect of laser parameters including laser frequency, laser pulse width, laser speed, and focal point position was investigated on the microstructure, geometrical dimensions of hardened zone (hardened width, hardened depth, and entry angle of hardened zone), and micro-hardness. In the specimens with higher cooling rate, martensitic phase (ά) is formed in the hardened zone, while in the specimens with lower cooling rate, combination of equaxied and acicular alpha phase is formed in the hardened zone. The laser speed has a significant effect on the overlapping factor compared to other laser variables. By increasing the laser speed, the cooling rate increase and the pulse overlapping decreases in the hardened zone. High cooling rate leads to the refinement of prior beta grain size in this zone. Combination of equiaxed and acicular alpha phase, as well as acicular martensitic phase, is observed in the transition zone. The martensitic phase is a dominant phase in location near the hardened zone. A laser power of 165 W, lase frequency of 14 Hz, pulse width of 22 ms, laser speed of 105 mm/min, and focal point position of + 3.5 mm are optimum parameters for obtaining the best laser surface hardening results. The presence of martensitic phase in the optimum sample causes an increase in the hardness about 36% as compare to the base metal.


Transformation surface hardening Pulsed Nd:YAG laser Ti-5Al-2.5Sn alloy Microstructure Hardness 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Froes FH (2015) Titanium: physical metallurgy, processing, and applications. ASM International, OhioGoogle Scholar
  2. 2.
    Donachie MJ (2000) Titanium: a technical guide. ASM international, OhioGoogle Scholar
  3. 3.
    Billinghurst Jr EE (1992) Tensile properties of cast titanium alloys: titanium-6Al-4V ELI and titanium-5Al-2.5 Sn ELI. NTRS, United StatesGoogle Scholar
  4. 4.
    Gao XL, Liu J, Zhang LJ, Zhang JX (2014) Effect of the overlapping factor on the microstructure and mechanical properties of pulsed Nd:YAG laser welded Ti6Al4V sheets. Mater Charact 93:136–149. CrossRefGoogle Scholar
  5. 5.
    Gautam GD, Pandey AK (2018) Pulsed Nd: YAG laser beam drilling: a review. Opt Laser Technol 100:183–215. CrossRefGoogle Scholar
  6. 6.
    Khorram A, Fakhraei O, Torkamany MJ (2017) Laser brazing of Inconel 718 and Inconel 600 with BNi-2 nickel-based filler metal. Int J Adv Manuf Technol 88:2075–2084. CrossRefGoogle Scholar
  7. 7.
    Sundqvist J, Manninen T, Heikkinen HP, Anttila S, Kaplan AFH (2018) Laser surface hardening of 11% Cr ferritic stainless steel and its sensitisation behaviour. Surf Coat Technol 344:673–679. CrossRefGoogle Scholar
  8. 8.
    Ghaini FM, Hamedi MJ, Torkamany MJ, Sabbaghzadeh J (2007) Weld metal microstructural characteristics in pulsed Nd:YAG laser welding. Scr Mater 56:955–958. CrossRefGoogle Scholar
  9. 9.
    Liu J, Watanabe I, Yoshida K, Atsuta M (2002) Joint strength of laser-welded titanium. Dent Mater 18:143–148. CrossRefGoogle Scholar
  10. 10.
    Steen WM (2003) Laser surface treatment. In: Laser Material Processing. Springer, LondonCrossRefGoogle Scholar
  11. 11.
    Dutta Majumdar J, Manna I (2011) Laser material processing. Int Mater 56:341–388. CrossRefGoogle Scholar
  12. 12.
    Shiue RK, Chen C (1992) Laser transformation hardening of tempered 4340 steel. Metall Mater Trans A 23:163–170. CrossRefGoogle Scholar
  13. 13.
    Ohtsu N, Yamane M, Kodama K, Wagatsuma K (2010) Surface hardening of titanium by pulsed Nd: YAG laser irradiation at 1064-and 532-nm wavelengths in nitrogen atmosphere. Appl Surf Sci 257:691–695. CrossRefGoogle Scholar
  14. 14.
    Chan CW, Lee S, Smith G, Sarri G, Ng CH, Sharba A, Man HC (2016) Enhancement of wear and corrosion resistance of beta titanium alloy by laser gas alloying with nitrogen. Appl Surf Sci 367:80–90. CrossRefGoogle Scholar
  15. 15.
    Kamat AM, Copley SM, Todd JA (2017) A two-step laser-sustained plasma nitriding process for deep-case hardening of commercially pure titanium. Surf Coat Technol 313:82–95. CrossRefGoogle Scholar
  16. 16.
    Badkar DS, Pandey KS, Buvanashekaran G (2010) Effects of laser phase transformation hardening parameters on heat input and hardened-bead profile quality of unalloyed titanium. Trans Nonferrous Metals Soc China 20:1078–1091. CrossRefGoogle Scholar
  17. 17.
    Badkar DS, Pandey DS, Buvanashekaran G (2009) Laser transformation hardening of unalloyed titanium using Nd:YAG laser. Int J Mater Sci 4:239–250Google Scholar
  18. 18.
    Badkar DS (2017) Study on laser hardening parameters of ASTM grade 3 pure titanium on an angle of entry of hardened bead profile and power density. IJMSE 3:019–034Google Scholar
  19. 19.
    Badkar DS, Pandey KS, Buvanashekaran G (2012) Application of the central composite design in optimization of laser transformation hardening parameters of commercially pure titanium using Nd: YAG laser. Int J Adv Manuf Technol 59:169–192. CrossRefGoogle Scholar
  20. 20.
    Hahn JD, Shin YC, Krane MJM (2007) Laser transformation hardening of Ti–6Al–4V in solid state with accompanying kinetic model. Surf Eng 23:78–82. CrossRefGoogle Scholar
  21. 21.
    Konstantino E, Altus E (1999) Fatigue life enhancement by laser surface treatments. Surf Eng 15:126–128. CrossRefGoogle Scholar
  22. 22.
    Abboud JH, West DRF (1992) Laser surface melting of Ti-10V-2Fe-3Al alloy. J Mater Sci Lett 11:1322–1326. CrossRefGoogle Scholar
  23. 23.
    Junaid M, Khan FN, Rahman K, Baig MN (2017) Effect of laser welding process on the microstructure, mechanical properties and residual stresses in Ti-5Al-2.5 Sn alloy. Opt Laser Technol 97:405–419. CrossRefGoogle Scholar
  24. 24.
    Khorram A, Jafari A, Moradi M (2018) Effect of linear heat input on the morphology and mechanical properties of Ti-6Al-4V welded using a CO2 laser. Lasers in Eng 40:49–64Google Scholar
  25. 25.
    Farshidianfar MH, Khajepour A, Gerlich AP (2016) Effect of real-time cooling rate on microstructure in laser additive manufacturing. J Mater Process Technol 231:468–478. CrossRefGoogle Scholar
  26. 26.
    Kannatey Asibu Jr E (2009) Principles of laser material processing. John Wiley and Sons, New JerseyCrossRefGoogle Scholar
  27. 27.
    Mahmoudi B, Torkamany MJ, Sabour Rouh Aghdam AR, Sabbaghzade J (2010) Laser surface hardening of AISI 420 stainless steel treated by pulsed Nd:YAG laser. Mater Des 31:2553–2560. CrossRefGoogle Scholar
  28. 28.
    Baruah M, Bag S (2017) Influence of pulsation in thermo-mechanical analysis on laser micro-welding of Ti6Al4V alloy. Opt Laser Technol 90:40–51. CrossRefGoogle Scholar
  29. 29.
    Li R, Jin Y, Li Z, Qi K (2014) A comparative study of high-power diode laser and CO2 laser surface hardening of AISI 1045 steel. J Mater Eng Perform 23:3085–3091. CrossRefGoogle Scholar
  30. 30.
    Bondar A, Fabrichnaya O (2006) Al-Sn-Ti (aluminium-tin-titanium). In: Effenberg G, Ilyenko S (eds) Light metal systems. Springer, BerlinGoogle Scholar
  31. 31.
    Moffatt WG (1976) The handbook of binary phase diagrams. Genium pub, CorpGoogle Scholar
  32. 32.
    Ahmed T, Rack HJ (1998) Phase transformations during cooling in α+ β titanium alloys. Mater Sci Eng A 243:206–211. CrossRefGoogle Scholar
  33. 33.
    Malinov S, Sha W, Guo Z, Tang C, Long A (2002) Synchrotron X-ray diffraction study of the phase transformations in titanium alloys. Mater Charact 48:279–295. CrossRefGoogle Scholar
  34. 34.
    Amaya-Vazquez MR, Sánchez-Amaya JM, Boukha Z, Botana FJ (2012) Microstructure, microhardness and corrosion resistance of remelted TiG2 and Ti6Al4V by a high power diode laser. Corros Sci 56:36–48. CrossRefGoogle Scholar
  35. 35.
    Shamir M, Junaid M, Khan FN, Taimoor AA, Baig MN (2017) A comparative study of electrochemical corrosion behavior in laser and TIG welded Ti–5Al–2.5 Sn alloy. JMRT.
  36. 36.
    Karpagaraj A, Siva shanmugam N, Sankaranarayanasamy S (2015) Some studies on mechanical properties and microstructural characterization of automated TIG welding of thin commercially pure titanium sheets. Mater Sci Eng A 640:180–189. CrossRefGoogle Scholar
  37. 37.
    Squillace A, Prisco U, Ciliberto S, Astarita A (2012) Effect of welding parameters on morphology and mechanical properties of Ti–6Al–4V laser beam welded butt joints. J Mater Process Technol 212:427–436. CrossRefGoogle Scholar
  38. 38.
    Gao XL, Zhang LJ, Liu J, Zhang JX (2013) A comparative study of pulsed Nd: YAG laser welding and TIG welding of thin Ti6Al4V titanium alloy plate. Mater Sci Eng A 559:14–21. CrossRefGoogle Scholar
  39. 39.
    Cao X, 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 Lasers Eng 47:1231–1241. CrossRefGoogle Scholar

Copyright information

© Springer-Verlag London Ltd., part of Springer Nature 2018

Authors and Affiliations

  • Ali Khorram
    • 1
    Email author
  • Akbar Davoodi Jamaloei
    • 2
  • Abed Jafari
    • 3
  1. 1.Department of Mechanical EngineeringKNToosi University of TechnologyTehranIran
  2. 2.Department of Materials EngineeringIsfahan University of TechnologyIsfahanIran
  3. 3.Department of Material And Metallurgy EngineeringIran University of Industries and Mines (IUIM)TehranIran

Personalised recommendations