Modulated fiber laser welding of high reflective AZ31

  • Lin-Jie Zhang
  • Xing-Jun Zhang
  • Jie Ning
  • Jian-Xun Zhang


Power sine modulation fiber laser welding (FLW) of AZ31 magnesium alloy was conducted. When the diameter of transmission fiber and focal spot was 400 μm and 0.4 mm, respectively, the average laser powers for penetrating a 2.7-mm-thick AZ31 plate at a welding speed of 5 m/min were reduced by about 33 % by using modulated FLW. The relationship between modulation parameters (i.e., amplitude, frequency, and average laser power) and weld depth which was closely related to the transfer efficiency of laser energy was studied through partial penetration laser welding test on 8-mm-thick AZ31 plate based on quadratic regression orthogonal design. It was found that influence of power modulation on laser welding of AZ31 alloy was highly dependent on laser power density. In the low power density range, laser energy coupling efficiency could be significantly improved by combining low amplitude with high frequency or high amplitude with low frequency. With the increasing of laser power density, the optimum frequency corresponding to maximum weld depth decreased, and the positive effect of the favorable combination of high amplitude and low frequency on laser energy coupling continuously weakened. When laser power density was high enough, power modulation had hardly positive effect on weld depth and energy coupling efficiency. It was argued that improvement of energy coupling efficiency in laser welding of AZ31 by using power modulation was due to the reduction in the portion of energy lost into surroundings. Finally, laser butt welding was conducted on 2.7-mm-thick AZ31 under the condition of high beam quality and the tensile strength of both butt-welded joint and base metal that was tested.


AZ31 magnesium alloy Power modulation Laser welding Regression orthogonal design Weld depth 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Friedrich HE, Mordike BL (2006) Magnesium technology. Springer, BerlinGoogle Scholar
  2. 2.
    Li CB, Liu LM (2013) Investigation on weldability of magnesium alloy thin sheet T-joints: arc welding, laser welding, and laser-arc hybrid welding. Int J Adv Manuf Technol 65(1–4):27–34CrossRefGoogle Scholar
  3. 3.
    Liao HT, Chen ZW (2013) A study on fiber laser micro-spot welding of thin stainless steel using response surface methodology and simulated annealing approach. Int J Adv Manuf Technol 67(5–8):1015–1025CrossRefGoogle Scholar
  4. 4.
    Zhang YN, Cao X, Wanjara P (2013) Microstructure and hardness of fiber laser deposited Inconel 718 using filler wire. Int J Adv Manuf Technol 69(9–12):2569–2581CrossRefGoogle Scholar
  5. 5.
    Chowdhury SM, Chen DL, Bhole SD, Powidajko E, Weckman DC, Zhou Y (2011) Microstructure and mechanical properties of fiber-laser-welded and diode-laser-welded AZ31 magnesium alloy. Metall Mater Trans A 42:1974–1989CrossRefGoogle Scholar
  6. 6.
    Chowdhury SH, Chen DL, Bhole SD, Powidajko E, Weckman DC, Zhou Y (2012) Fiber laser welded AZ31 magnesium alloy: the effect of welding speed on microstructure and mechanical properties. Metall Mater Trans A 43:2133–2147CrossRefGoogle Scholar
  7. 7.
    Harooni M, Kong F, Carlson B, Kovacevic R (2012) Mitigation of pore generation in laser welding of magnesium alloy AZ31B in lap joint configuration. ASME-International Mechanical Engineering Congress & Exposition Proceedings, Houston, TXGoogle Scholar
  8. 8.
    Harooni M, Carlson B, Kovacevic R (2014) Dual-beam laser welding of AZ31B magnesium alloy in zero-gap lap joint configuration. Opt Laser Technol 56:247–255CrossRefGoogle Scholar
  9. 9.
    Wang Z, Gao M, Tang H, Zeng X (2011) Characterization of AZ31B wrought magnesium alloy joints welded by high power fiber laser. Mater Charact 62:943–951CrossRefGoogle Scholar
  10. 10.
    Kuo TY, Jeng SL (2005) Porosity reduction in Nd–YAG laser welding of stainless steel and Inconel alloy by using a pulsed wave. J Phys D Appl Phys 38D:722–728CrossRefGoogle Scholar
  11. 11.
    Matsunawa A, Mizutani M, Katayama S, Seto N (2003) Porosity formation mechanism and its prevention in laser welding. Weld Int 17:431–437CrossRefGoogle Scholar
  12. 12.
    Kawaguchi I, Tsukamoto S, Arakane G, Honda H (2006) Characteristics of high power CO2 laser welding and porosity suppression mechanism with nitrogen shielding—study of high power laser welding phenomena. Weld Int 20:100–105CrossRefGoogle Scholar
  13. 13.
    Blackburn JE, Allen CM, Hilton PA, Li L, Hoque MI, Khan AH (2010) Modulated Nd: YAG laser welding of Ti–6Al–4V. Sci Technol Weld Join 15:433–439CrossRefGoogle Scholar
  14. 14.
    Stritt P, Weber R, Graf T, Muller S, Ebert C (2011) Utilizing laser power modulation to investigate the transition from heat-conduction to deep-penetration welding. Phys Procedia 12:224–231CrossRefGoogle Scholar
  15. 15.
    Heider A, Stritt P, Hess A, Weber R, Graf T (2011) Process stabilization at welding copper by laser power modulation. Phys Procedia 12:81–87CrossRefGoogle Scholar
  16. 16.
    Heider A, Sollinger J, Abt F, Boley M, Weber R, Graf T (2013) High-speed X-ray analysis of spatter formation in laser welding of copper. Phys Procedia 41:112–118CrossRefGoogle Scholar
  17. 17.
    Haferkamp H, Goede M, Bormann A, Cordini P (2001) Laser beam welding of magnesium alloys—new possibilities using filler wire and arc welding. Proc LANE Laser Assist Net Shape Eng 3:333–338Google Scholar
  18. 18.
    Fujinaga S, Takenaka H, Narikiyo T, Katayama S, Matsunawa A (2000) Direct observation of keyhole behaviour during pulse modulated high-power Nd:YAG laser irradiation. J Phys D Appl Phys 33:492CrossRefGoogle Scholar
  19. 19.
    Kaplan AFH, Mizutani M, Katayama S (2002) Unbounded keyhole collapse and bubble formation during pulsed laser interaction with liquid zinc. J Phys D Appl Phys 35:1218–1228CrossRefGoogle Scholar

Copyright information

© Springer-Verlag London 2014

Authors and Affiliations

  • Lin-Jie Zhang
    • 1
  • Xing-Jun Zhang
    • 1
  • Jie Ning
    • 1
  • Jian-Xun Zhang
    • 1
  1. 1.State Key Laboratory of Mechanical Behavior for MaterialsXi’an Jiaotong UniversityXi’anChina

Personalised recommendations