Microstructure and mechanical properties of GTAW welded joints of AA6105 aluminum alloy
Abstract
Gas Tungsten Arc Welding (GTAW) is one of the most used methods to weld aluminum. This work investigates the influence of welding parameters on the microstructure and mechanical properties of GTAW welded AA6105 aluminum alloy joints. AA6105 alloy plates with different percent values of cold work were joined by GTAW, using various combinations of welding current and speed. The fusion zone, in which the effects of cold work have disappeared, and the heat affected zone of the welded samples were examined under optical and scanning electron microscopes, additionally, mechanical tests and measures of Vickers microhardness were performed. Results showed dendritic morphology with solute micro- and macrosegregation in the fusion zone, which is favored by the constitutional supercooling when heat input increases. When heat input increased and welding speed increased or remained constant, greater segregation was obtained, whereas welding speed decrease produced a coarser microstructure. In the heat affected zone recrystallization, dissolution, and coarsening of precipitates occurred, which led to variations in hardness and strength.
Keywords
AA6105, cold work, GTAW, secondary phase, ultimate tensile strength, welding current, welding speed, weld bead hardness
References
- R. Messler, Principles of Welding. Singapore: John Wiley & Sons, 1999. DOI: http://dx.doi.org/10.1002/9783527617487. DOI: https://doi.org/10.1002/9783527617487
- G. Singh, S. Kumar, and A. Singh, “Influence of Current on Microstructure and hardness of butt welding aluminium AA6082 using GTAW process,” Int. J. Res. Mech. Eng. Technol., vol. 3 (2), pp. 143-146, Oct. 2013.
- F. Gulshan and Q. Ahsan, “Effect of heat input on the structure and properties of aluminium weldment TIG welded with 4043 filler rod,” Chem. Mater. Eng., vol. 2 (2), pp. 25-32, 2014. DOI: http://dx.doi.org/10.13189/cme.2014.020201. DOI: https://doi.org/10.13189/cme.2014.020201
- L. H. Shah, N. Azhani, A. Razak, A. Juliawati, and M. Ishak, “Investigation on the mechanical properties of TIG welded AA6061 alloy weldments using different aluminium fillers,” Int. J. Eng. Technol., vol. 2 (2), pp. 116-120, Aug. 2013. DOI: https://doi.org/10.5176/2251-3701_2.2.81
- P. K. Palani and M. Saju, “Modelling And optimization of process parameters for TIG welding of Aluminium-65032 using response surface methodology,” Int. J. Eng. Res. Appl., vol. 3 (2), pp. 230-236, 2013.
- L. Singh, R. Singh, N. K. Singh, D. Singh, and P. Singh, “An evaluation of TIG welding parametric influence on tensile strength of 5083 aluminium alloy,” Int. J. Mech. Aerospace, Ind. Mechatronics Eng., vol. 7 (11), pp. 1262-1265, 2013.
- V. Gautam, “Optimization of process parameters for Gas Tungsten Arc Welding of AA1100 Aluminium Alloy,” Int. J. Curr. Eng. Technol., vol. 4 (2), pp. 788-792, 2014.
- AWS, “Welding Handbook,” Fundamentals of Welding, vol. 4. pp. 69.53-69, 1972.
- AWS, “A5.10 Specification for Bare Aluminum and Aluminum-Alloy Welding Electrodes and Rods.” 2007.
- ASTM International, “ASTM E3-11, Standard guide for preparation of metallographic specimens,” vol. 3 (1), 2011.
- ASTM International, “ASTM B557-14, Standard test methods for tension testing wrought and cast aluminum- and magnesium-alloy products,” vol. 2 (2), 2014.
- ASTM International, “ASTM E112 - 13 Standard Test Methods for Determining Average Grain Size,” vol. 3 (1), 2013.
- K. Sindo, Welding Metallurgy, 2da ed. USA: John Wiley & Sons, 2003.
- Y. Birol, “The effect of homogenization practice on the microstructure of AA6063 billets,” J. Mater. Process. Technol., vol. 148 (2), pp. 250-258, May. 2004. DOI: http://dx.doi.org/10.1016/j.jmatprotec.2004.01.056. DOI: https://doi.org/10.1016/j.jmatprotec.2004.01.056
- S. Missori and A. Sili, “Mechanical behaviour of 6082-T6 aluminium alloy welds,” Metal. Sci. Technol., vol. 18 (1), pp. 12-18, 2000.
- H. Guo, J. Hu, and H. L. Tsai, “Formation of weld crater in GMAW of aluminum alloys,” Int. J. Heat Mass Transf., vol. 52 (23-24), pp. 5533–5546, Nov. 2009. DOI: http://dx.doi.org/10.1016/j.ijheatmasstransfer.2009.06.028. DOI: https://doi.org/10.1016/j.ijheatmasstransfer.2009.06.028
- “ASM Handbook Volume 3: Alloy Phase Diagrams - ASM International.” [Online]. Available: http://www.asminternational.org/online-catalog/phase-diagrams/-/journal_content/56/10192/06479G/PUBLICATION. [Accessed: 14-May-2016].
- M. Nicolas and A. Deschamps, “Characterisation and modelling of precipitate evolution in an Al–Zn–Mg alloy during non-isothermal heat treatments,” Acta Mater., vol. 51 (20), pp. 6077-6094, Dec. 2003. DOI: http://dx.doi.org/10.1016/S1359-6454(03)00429-4. DOI: https://doi.org/10.1016/S1359-6454(03)00429-4