The effects of mix activated fluxes on the penetrations, microstructures and mechanical properties of tungsten inert gas (TIG) welded AZ31 magnesium alloy joints were studied. The results showed that an increase in the amount of TiO2 coating improved the weld penetration and depth/width ratio of the TIG welded AZ31 magnesium alloy seams. The α-Mg grains of the fusion zone (FZ) became fine gradually with the addition of CaF2 coating but coarsened sharply when the amount of TiO2 coating was over 70%. In addition, the porosities and total length of solidification cracks in the FZ were reduced by the CaF2 and TiO2 coatings. The ultimate tensile strength value of the welded joints increased with the addition of TiO2 coating but decreased sharply when more TiO2 coating was adopted.
WestengenH: ‘Magnesium die casting: from ingots to automotive parts’, J. Light Met., 2000, 58, 44–52.
2.
MunitzA, CotlerC, SternA, KohnG: ‘Mechanical properties and microstructure of gas tungsten arc welded magnesium AZ91D plates’, Mater. Sci. Eng. A, 2001, A302, 68–73.
3.
CoelhoRS, KostkaA, PintoH, RiekehrS, KocakM, PyzallaAR: ‘Microstructure and mechanical properties of magnesium alloy AZ31B laser beam welds’, Mater. Sci. Eng. A, 2008, A485, 20–30.
4.
SuSF, HuangJC, LinHK, HoNJ: ‘Electron beam welding behavior in Mg–Al based alloys’, Mater. Sci. Eng. A, 2001, A33, 1461–2002.
5.
XieGM, MaZY, GengL, ChenRS: ‘Microstructural evolution and enhanced superplasticity in friction stir processed Mg–Zn–Y–Zr alloy’, J. Mater. Res., 2008, 23, 1207–1213.
6.
GurevichSM, ZamkovVN, KushmienkoNA: ‘Improving the penetration of titanium alloys when they are welded by argon tungsten arc process’, Avtom. Svarka., 1965, 9, 1–4.
7.
GurevichSM, ZamkovVN: ‘Welding titanium with a nonconsumable electrode using fluxes’, Avtom. Svarka., 1966, 12, 13–16.
8.
ModenesiPJ, ApolinarioER, PereiraIM: ‘TIG welding with single-component fluxes’, J. Mater. Process. Technol., 2000, 99, 260–265.
9.
LiQM, WangXH, ZouZD, WuJ: ‘Effect of activating flux on arc shape and arc voltage in tungsten inert gas welding’, Trans. Nonferrous Met. Soc. China, 2007, 17, 486–490.
10.
LuSP, HidetoshiF, HiroyukiS, KiyoshiN: ‘Mechanism and optimization of oxide fluxes for deep penetration in gas tungsten arc welding’, Metall. Mater. Trans. A, 2003, 34A, 1901–1907.
11.
LuSP, HidetoshiF, HiroyukiS, ManabuT, KiyoshiN: ‘Weld penetration and Marangoni convection with oxide fluxes in GTA welding’, Mater. Trans., 2002, 43, 2926–2931.
12.
XuJL, Chen ChenC: ‘The research of materials microstructure analysis’, Acta. Metrologica. Sin., 2004, 4, 369–373.
13.
LuSP, FujiiH, NogiK: ‘Marangoni convection and weld shape variations in Ar–O2 and Ar–CO2 shielded GTA welding’, Mater. Sci. Eng. A, 2004, A380, 290–297.
14.
ModenesiPJ, ApolinarioER, PereiraIM: ‘TIG welding with single-component fluxes’, J. Mater. Process. Technol., 2000, 99, 260–265.
15.
XuYL, DongZB, WeiYH, YangCL: ‘Marangoni convection and weld Shape variation in A-TIG welding process’, Theory Appl. Fract. Mech., 2007, 48, (2), 178–186.
16.
WangLZ, ShenJ, XuN: ‘Effects of TiO2 coating on the microstructures and mechanical properties of tungsten inert gas welded AZ31 magnesium alloy joints’, Mater. Sci. Eng. A, 2011, A528, 7276–7284.
17.
HowseDS, LucasW: ‘Investigation into arc constriction by active fluxes for tungsten inert gas welding’, Sci. Technol. Weld. J., 2000, 5, (3), 189–193.
18.
LeconteS, PaillerdP, SaindrenanJ: ‘Effect of fluxes containing oxides on tungsten inert gas welding process’, Sci. Technol. Weld. Join., 2006, 11 (1), 43–47.
19.
LiangGL, YuanSQ: ‘Study on the temperature measurement of AZ31B magnesium alloy in gas tungsten arc welding’, Mater. Lett., 2008, 62, 2282–2284.
HiraiK, SomekawaH, TakigawaY, HigashiK: ‘Effects of Ca and Sr addition on mechanical properties of a cast AZ91 magnesium alloy at room and elevated temperature’, Mater. Sci. Eng. A, 2005, A403, 276–280.
22.
ShenJ, YouGQ, LongSY, PanFS: ‘Abnormal macropore formation during double-sided gas tungsten arc welding of magnesium AZ91D alloy’, Mater. Charact., 2008, 59, 1059–1065.
23.
ZengK, KlassenT, OelerichW, BormannR: ‘Critical assessment and thermodynamic modeling of the Mg–H system’, Int. J. Hydrogen Energy, 1999, 24, 989–1004.
24.
AminA: ‘Pulse current parameters for arc stability and controlled metal transfer in arc welding’, Met. Constr., 1983, 15, 272–278.
25.
EssersWG, GompelMRMVan: ‘Arc control with pulsed GMA welding’, Weld. J., 1984, 6, 26–32.
26.
WuML, YuSR, ZhangGJ, XiongJH: ‘Study on getting rid of welding porosity of titanium alloy by fluxes’, Hot Working Technol., 2006, 15, 36–38.
27.
TangB, LiSS, WangXS: ‘An investigation on hot-crack mechanism of Ca addition into AZ91D alloy’, J. Mater. Sci., 2005, 40, 2931–2936.
28.
SunZ, PanD, WeiJ: ‘Comparative evaluation of tungsten inert gas and laser welding of AZ31 magnesium alloy’, Sci. Technol. Weld. Join., 2002, 7, 343–351.
