Abstract
In the present study, the effect of heat input of gas tungsten arc welding on the microstructure and mechanical properties of AZ91 magnesium alloy was investigated. The microstructural studies were performed by using an optical microscope and scanning electron microscope equipped with energy dispersive X-ray spectroscopy, and tensile test was used to evaluate the mechanical properties. It was shown that, comparing to the base metal, a fine microstructure of α(Mg) and Mg17Al12 phase is formed in the weld metal and the size of α(Mg) phase slightly increased with heat input during welding process. The results also indicated that the thickness of partially melted zone increased with heat input. Tensile strength of welded samples was lower than that of the base metal and it decreases with increasing heat input. Failure of the welded specimens accrues in the partially melted zone. Studying of fracture surface revealed that the interface of α(Mg) and Mg17Al12 compound acts as crack initiation and growth path during the tensile test. Formation of cleavage steps in the fracture surface was the dominant fracture mechanism during tensile tests.
Similar content being viewed by others
Data Availability
Data and materials are available.
Code availability
Not applicable.
References
Munitz A, Cotler C, Stern A, Kohn G (2001) Mechanical properties and microstructure of gas tungsten arc welded magnesium AZ91D plates. Mater Sci Eng A 302:68–73
Kumar DS, Sasanka CT, Ravindra K, Suman KN (2015) Magnesium and its alloys in automotive applications–a review. J Mater Sci Technol 4:12–30
Nami B, Miresmaeili SM, Jamshidi F, Khoubrou I (2019) Effect of Ca addition on microstructure and impression creep behavior of cast AZ61 magnesium alloy. Trans Nonferrous Metals Soc China 29:2056–2065
Khomamizadeh F, Nami B, Khoshkhooei S (2005) Effect of rare-earth element additions on high-temperature mechanical properties of AZ91 magnesium alloy. Metall Mater Trans A 36:3489–3494
Tekumalla S, Gupta M (2017) An insight into ignition factors and mechanisms of magnesium based materials: a review. Mater Des 113:84–98
Adamiec J, Roskosz S, Jarosz R (2007) Repair of magnesium alloy castings by means of welding and pad welding. Mater Manuf Eng 22:21–24
Hosseini VA, Aashuri H, Kokabi A (2013) Mechanisms of joint formation throughout semisolid stir welding of AZ91 magnesium alloy. Trans Nonferrous Metals Soc China 23:2585–2590
Robson JD, Cui S, Chen ZW (2010) Incipient melting during friction stir processing of AZ91 magnesium castings. Mater Sci Eng A 527:7299–7304
Cerri E, Leo P (2014) Effect of friction stir processing on microstructure and mechanical properties of a HPDC magnesium alloy. Mater Sci Forum 783:1735–1740
Jiang J, Zhang Z (2008) The study on the plasma arc weld bonding process of magnesium alloy. J Alloys Compd 466:368–372
Wahba M, Mizutani M, Kawahito Y, Katayama S (2012) Laser welding of die-cast AZ91D magnesium alloy. Mater Des 33:569–576
Cao XJ, Jahazi M, Immarigeon JP, Wallace W (2006) A review of laser welding techniques for magnesium alloys. J Mater Process Technol 171:188–204
Watkins KG, (2003) Laser welding of magnesium alloys, in: Magnesium technology 2003, Proceedings of the Symposium held during the 2003 TMS Annual Meeting, San Diego, CA, United States, 153–156.
Luo Y, Ye H, Du C, Xu H (2012) Influence of focusing thermal effect upon AZ91D magnesium alloy weld during vacuum electron beam welding. Vacuum 86:1262–1267
Luo Y, Liu J (2011) Microstructural evolution in AZ91D magnesium alloy during electron beam welding. Vacuum 85:1004–1010
Abbas M, Khan A, Ali M, Kamran MA, Azam K, Shakoor A (2014) Effect of weld current and weld speed on the micro structure and tensile properties of magnesium alloy specimens during tungsten inert gas welding, University of Engineering and Technology Taxila. Tech J 19:35
Kumar SP, Vigneshwar M, Selvamani ST, Prakash AS, Hariprasath P (2017) The comparative analysis on friction stir welded and gas tungsten arc welded AZ91 grade magnesium alloy butt joints. Mater Today Proc 4:6688–6696
Yuan T, Luo Z, Kou S (2017) Mechanism of grain refining in AZ91 Mg welds by arc oscillation. Sci Technol Weld Join 22:97–103
Yuan T, Chai X, Luo Z, Kou S (2015) Predicting susceptibility of magnesium alloys to weld-edge cracking. Acta Mater 90:242–251
Stern A, Munitz A (1999) Partially melted zone microstructural characterization from gas tungsten-arc bead on plate welds of magnesium AZ91 alloy. J Mater Sci Lett 18:853–855
Zhu T, Chen ZW, Gao W (2008) Microstructure formation in partially melted zone during gas tungsten arc welding of AZ91 Mg cast alloy. Mater Charact 59:1550–1558
Dahle AK, Lee YC, Nave MD, Schaffer PL, St John DH (2001) Development of the as-cast microstructure in magnesium–aluminium alloys. J Light Met 1:61–72
Carlone P, Palazzo GS (2015) Characterization of TIG and FSW weldings in cast ZE41A magnesium alloy. J Mater Process Technol 215:87–94
Minnick WH, Prosser MA (1996) Gas tungsten arc welding handbook. The Goodheart-Willcox Company, Tinley Park
Braszczyńska-Malik KN, Mróz M (2011) Gas-tungsten arc welding of AZ91 magnesium alloy. J Alloys Compd 509:9951–9958
Blawert C, Fechner D, Höche D, Heitmann V, Dietzel W, Kainer KU, Živanović P, Scharf C, Ditze A, Gröbner J, Schmid-Fetzer R (2010) Magnesium secondary alloys: alloy design for magnesium alloys with improved tolerance limits against impurities. Corros Sci 52:2452–2468
Nami B, Razavi H, Mirdamadi S, Shabestari SG, Miresmaeili SM (2010) Effect of Ca and rare earth elements on impression creep properties of AZ91 magnesium alloy. Metall Mater Trans A 41:1973–1982
Nami B, Shabestari SG, Razavi H, Mirdamadi S, Miresmaeili SM (2011) Effect of Ca, RE elements and semi-solid processing on the microstructure and creep properties of AZ91 alloy. Mater Sci Eng A 528:1261–1267
Khoubrou I, Nami B, Miresmaeili SM (2020) Investigation on the creep behavior of AZ91 magnesium alloy processed by severe plastic deformation. Met Mater Int 26:196–204
Kou S (1987) Welding metallurgy. Cambridge Univ Press, Cambridge
Nave MD, Dahle AK, StJohn DH (2000) Eutectic growth morphologies in magnesium-aluminium alloys. Magnes Technol 1:233–242
Zhu T, Chen ZW, Gao W (2006) Incipient melting in partially melted zone during arc welding of AZ91D magnesium alloy. Mater Sci Eng A 416:246–252
Zhu TP, Chen ZW, Gao W (2007) Partial melting and re-solidification in partially melted zone during gas tungsten arc welding of AZ91 cast alloy. Trans Nonferrous Metals Soc China 17:342–346
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Recommended for publication by Commission XV - Design Analysis and Fabrication of Welded Structures
Rights and permissions
About this article
Cite this article
Assar, A., Nami, B., Arab, N.B.M. et al. Effect of heat input of TIG repair welding on microstructure and mechanical properties of cast AZ91 magnesium alloy. Weld World 65, 1131–1143 (2021). https://doi.org/10.1007/s40194-021-01100-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s40194-021-01100-8