Microstructure characteristics in TIG welded joint of Mg/Al dissimilar materials

Liu, Peng; Li, Yajiang; Geng, Haoran; Wang, Juan

doi:10.1016/j.matlet.2006.07.010

Cited by 146 publications

(51 citation statements)

References 2 publications

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“…The friction of ceramics against metallic materials, such as PEO coatings against steelinthepresent case,is accompaniedby the continual renovation of the friction contact area. Owing to this, the chemical interaction is accelerated in the contacting area, resulting in a rise in coefficient of friction [18,[26][27][28]. These steady state values are maintained till the end of the test, which implies that these coatings survived the test without failure at 2 N load.…”

Section: Wear Behaviormentioning

confidence: 99%

“…have emerged as effective means to improve the wear resistance of Mg alloys [3][4][5][6][7]. Among these coating processes, LSA and PEO have gained attention during recent years due to the exhibited increased wear resistance [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. PEO coatings are basically conversion coatings performed at high voltages in an aqueous electrolyte, which rely on repetitive local dielectric breakdown and formation of plasma modifying the coating with the incorporation of species from the electrolyte [28].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wear behavior of plasma electrolytic oxidation (PEO) and hybrid coatings of PEO and laser on MRI 230D magnesium alloy

Rapheal

Kumar

Blawert³

et al. 2011

Wear

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Section: Wear Behaviormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wear behavior of plasma electrolytic oxidation (PEO) and hybrid coatings of PEO and laser on MRI 230D magnesium alloy

Rapheal

Kumar

Blawert³

et al. 2011

Wear

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“…phase diagram if the cooling rate would be infinitely slow (i.e., under equilibrium cooling). Such b-Mg 17 Al 12 precipitates were also observed in the FZ of laser/arc hybrid [39] ; TIG [40] ; electron beam [41] ; gas tungsten arc [42] ; and double-sided arc-welded [43] Mg joints.…”

Section: A Microstructurementioning

confidence: 75%

Microstructure and Mechanical Properties of Fiber-Laser-Welded and Diode-Laser-Welded AZ31 Magnesium Alloy

Chowdhury

Chen

Bhole

et al. 2010

Metall Mater Trans A

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The microstructures, tensile properties, strain hardening, and fatigue strength of fiber-laserwelded (FLW) and diode-laser-welded (DLW) AZ31B-H24 magnesium alloys were studied. Columnar dendrites near the fusion zone (FZ) boundary and equiaxed dendrites at the center of FZ, with divorced eutectic b-Mg 17 Al 12 particles, were observed. The FLW joints had smaller dendrite cell sizes with a narrower FZ than the DLW joints. The heat-affected zone consisted of recrystallized grains. Although the DLW joints fractured at the center of FZ and exhibited lower yield strength (YS), ultimate tensile strength (UTS), and fatigue strength, the FLW joints failed at the fusion boundary and displayed only moderate reduction in the YS, UTS, and fatigue strength with a joint efficiency of~91 pct. After welding, the strain rate sensitivity basically vanished, and the DLW joints exhibited higher strain-hardening capacity. Stage III hardening occurred after yielding in both base metal (BM) and welded samples. Dimple-like ductile fracture characteristics appeared in the BM, whereas some cleavage-like flat facets together with dimples and river marking were observed in the welded samples. Fatigue crack initiated from the specimen surface or near-surface defects, and crack propagation was characterized by the formation of fatigue striations along with secondary cracks.

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“…Moreover, the output of pulsed current can also strengthen the molten pool stirring to produce refined grains. In terms of weldability [6], AA6063 suffers from a substantial decline in strength after welding. The loss of strength is because the rapid melting and solidification process makes all the strengthening precipitates dissolve into the aluminium matrix and complete dissolution of the precipitates can not take place in weld metal and overaging appear in HAZ and meanwhile solute segregation and grain coarsening also come up [11].…”

Section: Imentioning

confidence: 99%

Effect of Post Weld Heat Treatment on Properties of ACTIG Welded Aa6063 Aluminium Alloy Joint

Verma¹

2017

IJRASET

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AA6063 aluminium alloy joints were fabricated by alternating current tungsten inert gas (ACTIG) welding process and the effects of post weld heat treatment (PWHT) on the tensile properties, impact strength, microstructure, microhardness and fractography of the welded joints were investigated. The ACTIG welding process was adopted because it bears higher strength, more ductility and no apparent microstructure defect. The welded samples were divided into as-welded (AW) sample and PWHT sample. The PWHT method used on the samples was solution treatment (535 °C, 2h), water quenching and artificial aging (165 °C, 18h). The experimental results show that, compared with the AW samples, the microstructure characteristics and mechanical properties of the AA6063 joints after PWHT were significantly improved. The improvement of ultimate tensile strength, and impact strength are 3.72% and 22.22% respectively. Keywords: GTAW, PWHT, SEM, EDS. I.INTRODUCTION Aluminium alloys have been widely used in many fields such as the construction, transportation and aerospace owing to their excellent performance, including light weight, high strength and ductility, good corrosion resistance and abundant resources [1]. Among the various heat-treatable aluminium alloys, AA6063 aluminium alloys possess a good combination of strength and toughness with excellent weldability and extrudability, which makes this alloy an preferred choice for Automotive outer bodypanels, railcars, etc. buildings (doors, windows, ladder, etc), marine(offshore structure, etc), heating(brazing sheets, etc)]. This type of aluminium alloy contains Magnesium(Mg) and Silicon(Si) as its major alloying element. Welding is one of the most common joining methods for aluminium alloys. Tungsten inert gas (TIG) process and gas metal arc welding (GMAW) are the most-used welding processes [2]. GMAW possesses advantages of high deposition rate, high welding speed and deep penetration, but excessive heat input brings particularly in welding of thin aluminium sheets. Hence, TIG welding process is preferred over gas metal arc welding so as to obtain high quality weldments [3]. The TIG welding used in this work as AC tungsten inert gas (ACTIG). Moreover, the output of pulsed current can also strengthen the molten pool stirring to produce refined grains. In terms of weldability [6], AA6063 suffers from a substantial decline in strength after welding. The loss of strength is because the rapid melting and solidification process makes all the strengthening precipitates dissolve into the aluminium matrix and complete dissolution of the precipitates can not take place in weld metal and overaging appear in HAZ and meanwhile solute segregation and grain coarsening also come up [11]. Therefore, the post weld heat treatment (PWHT) can be implemented as an effective method of minimizing the softening and improving the properties of welded joints. PWHT has been demonstrated to be a practical option to regain the strength of the joints by modifying the size, shape and distribution of th...

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Microstructure characteristics in TIG welded joint of Mg/Al dissimilar materials

Cited by 146 publications

References 2 publications

Wear behavior of plasma electrolytic oxidation (PEO) and hybrid coatings of PEO and laser on MRI 230D magnesium alloy

Wear behavior of plasma electrolytic oxidation (PEO) and hybrid coatings of PEO and laser on MRI 230D magnesium alloy

Microstructure and Mechanical Properties of Fiber-Laser-Welded and Diode-Laser-Welded AZ31 Magnesium Alloy

Effect of Post Weld Heat Treatment on Properties of ACTIG Welded Aa6063 Aluminium Alloy Joint

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