Effect of post weld heat treatments on microstructure and mechanical properties of friction stir welded joints of Al–Zn–Mg alloy AA7039

Sharma, Chaitanya; Dwivedi, Dheerendra Kumar; Kumar, Pradeep

doi:10.1016/j.matdes.2012.06.018

Cited by 122 publications

(44 citation statements)

References 22 publications

(38 reference statements)

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“…Reduction in strength of 7039 alloy after friction stir processing can be attributed to recrystallization and reversion (dissolution of strengthen MgZn 2 precipitates) caused by friction heat generated during friction stir processing. These findings are in agreement with published research on FSW of AA 7039 alloy [13]. Marginally higher tensile strength of sample taken from the transverse direction than that of the sample taken from longitudinal direction from friction stir processed plate is attributed to difference in thermal cycle and plastic deformation experienced by the 7039 alloy in two directions i.e.…”

Section: B Tensile Propertiessupporting

confidence: 92%

“…The metal in deformed state under the influence of external heat show greater structural instability than in annealed condition. This is analogous to the abnormal grain growth observed in stir zone and HAZ of friction stir weld joint of 7039 alloy during post weld heat treatment [13]. The refinement of micro-constituents in stir zone is expected to enhance the mechanical properties especially ductility and fatigue resistance.…”

Section: Resultsmentioning

confidence: 55%

“…AA 7039 is an Al-Zn-Mg alloy of medium strength and is commonly used for making components of railway transport system, military vehicles, high speed trains, ships etc. [13]. Therefore, to fill up this gap, in present work, attempts were made to study the influence of single and multi pass friction stir processing on the structure and mechanical properties of AA 7039 alloy.…”

Section: Introductionmentioning

confidence: 99%

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Friction Stir Processing of AA 7039 Alloy

2014

International Academy of Engineers (IA-E) Dec. 30-31, 2014 Bangkok, Thailand

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Abstract-Friction stir processing (FSP) is an effective solid state surface modification technique used to improve the surface properties of metals like aluminium, and titanium controlled structural refinement. In present work, friction stir processing of 5 mm thick plate of Al-Zn-Mg alloy (AA 7039) was carried out using a conical pin and overlap of 50%. Modified surfaces were characterized in respect of macrostructure, microstructure, hardness and tensile properties. It was observed that friction stir processing refined the microstructure of AA 7039 alloy and increased the ductility (%elongation). However, tensile strength and hardness were found to be adversely affected. Hardness has been found to be increased with number of passes during friction stir processing.

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Section: B Tensile Propertiessupporting

confidence: 92%

Section: Resultsmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

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Friction Stir Processing of AA 7039 Alloy

2014

International Academy of Engineers (IA-E) Dec. 30-31, 2014 Bangkok, Thailand

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“…PWHT has been demonstrated to be a practical option to regain the strength of the joints by modifying the size, shape and distribution of the secondary strengthening particles [4]. A few research works have studied the aging impact on mechanical properties and microstructure of AA6063 [9]. Hence, the present investigation is carried out to study the influence of PWHT on the properties of ACTIG welded AA6063 aluminium alloy joints.…”

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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“…Hargopal et al [5] et al investigates the influence of welding parameter in mechanical properties of Al-65032 alloy with Taguchi's method. Sharma et al [6] the author investigates the effect of welding parameter like welding speed, voltage and current on the depth of penetration of welded joint. Chandel et al [7] derive a relationship between the bead height, bead width, melting rate, depth of penetration in terms of current, voltage, electrode diameter, electrode extension in submerged arc welding.…”

Section: Introductionmentioning

confidence: 99%

Microstructure Analysis of Arc Welded Mild Steel Plates

Khamari

Sahu

Biswal

2018

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. In order to perform arc welding, mild steel plates of variable thickness i.e. 5 mm, 6 mm and 8mm has been chosen as parent material. Total nine numbers of experiments were conducted by considering the two factors and three levels of design according to Taguchi method. The welding current and material thickness has been selected as variable input parameters with 5mm, 6 mm, 8mm level of material thickness and 90 A, 100A, 110A level of current respectively. The microstructure of the all the nine welded material has been analysed with the help of an optical microscope which is interfaced computer. The results of microstructure obtained from the microscopic investigation have been shown. The effect of current and material on the weldment microstructure is investigated. The result also shows that the coarse structure is formed in fusion zone and fine structure is formed in Heat affected region.

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Effect of post weld heat treatments on microstructure and mechanical properties of friction stir welded joints of Al–Zn–Mg alloy AA7039

Cited by 122 publications

References 22 publications

Friction Stir Processing of AA 7039 Alloy

Friction Stir Processing of AA 7039 Alloy

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

Microstructure Analysis of Arc Welded Mild Steel Plates

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