scholarly journals Post corrosion tensile strength and failure of dissimilar friction stir welded aluminium alloys

2020 ◽  
Vol 326 ◽  
pp. 04008
Author(s):  
Madhav Raturi ◽  
Anirban Bhattacharya
Keyword(s):  
Tensile Strength ◽  
Aluminium Alloys ◽  
Base Material ◽  
Fracture Morphology ◽  
Stir Zone ◽  
Tensile Failure ◽  
Friction Stir ◽  
Corrosive Solution ◽  
Dissimilar Weld ◽  
Dissimilar Friction Stir Welding

The present study efforts towards appraising the effects of corrosion on the tensile and fracture behaviour of dissimilar friction stir welding (FSW) of aluminium alloys. Three different dissimilar FSW joints obtained between AA6061-T6 and AA7075-T651, AA6061-T6 and AA2014-T6, AA7075-T651 and AA2014-T6, using threaded pin profile with three flat faces (TIF) tool at rotational speed of 1200 rpm and welding speed of 98 mm/min. The maximum joint tensile strength was achieved for AA7075-AA2014 joints followed by AA6061-AA2014 and least recorded for AA6061-AA7075 for as obtained FSW joints (non-corroded). The joints are further immersed into a corrosive solution for 1, 2, 7 and 14 days duration. The corrosion occurred all over the joint but much accelerated rate of exfoliation corrosion exists away from stir zone near the confluence of heat affected zone and base material irrespective of the advancing or retreating side. With increase in corrosion time the location of tensile failure shifted towards corroded region (AA6061-T6) instead of stir zone in dissimilar weld joint AA6061-AA2014, whereas it remained unchanged for other two joints. The fractured surfaces of AA6061-AA2014 FSW joints reveals the articulated view of pits and fracture morphology advocating the loss in YS, UTS and % elongation with increases in immersion duration.

The Effect of Tool Rotation Speed on Hardness, Tensile Strength, and Microstructure of Dissimilar Friction Stir Welding of Dissimilar AA5083 and AA6061-T6 Alloys

2021 ◽  
Vol 892 ◽  
pp. 159-168
Author(s):  
Arif Wahyudianto ◽  
Mochammad Noer Ilman ◽  
Priyo Tri Iswanto ◽  
Kusmono ◽  
Akhyar Akhyar
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Rotation Speed ◽  
Base Material ◽  
Metallographic Analysis ◽  
Friction Stir ◽  
Dissimilar Alloys ◽  
Dissimilar Friction Stir Welding ◽  
Solid State Joining ◽  
Tool Rotation

The welding between two different grades of aluminum alloy, specifically AA5083 and AA6061-T6, is very difficult to obtain optimal results when using conventional welding methods such as TIG/MIG welding. Therefore, a solid-state joining technique is highly recommended to overcome these problems, one of which is friction stir welding (FSW). The effect of rotation speed on microstructure, microhardness, and tensile properties of dissimilar Friction Stir welded AA5083 and AA6061-T6 aluminum alloys were investigated. Three different rotation speeds (910, 1500, and 2280 rpm) were used to weld the dissimilar alloys. The metallographic analysis of joints showed the presence of various zones such as BM (base material), HAZ (heat affected zone), TMAZ (thermo-mechanically affected zone), and NZ (nugget zone) were observed and analyzed by mean of optical and scanning electron microscope. The results showed that increasing the rotation speed from 900 to 2280 rpm made grain coarsening in NZ and the mass distribution of the material is more evenly distributed, as well as increased hardness and tensile strength of the joint. The highest values in microhardness in NZ and tensile strength at the join were founded at the speed of 2280 rpm and 1500 rpm which was similar to 2280 rpm, respectively.

scholarly journals Assessment of Microstructure and Mechanical Properties of Stir Zone Seam of Friction Stir Welded Magnesium AZ31B through Nano-SiC

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1044 ◽  
Author(s):  
Vijayakumar Subramani ◽  
Balaji Jayavel ◽  
Ramesh Sengottuvelu ◽  
Prince Lazar
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Fracture Mode ◽  
Welded Joints ◽  
Fracture Morphology ◽  
Stir Zone ◽  
Nano Composite ◽  
Volume Percentage ◽  
Friction Stir ◽  
Volume Fractions

In the present study, silicon carbide nanoparticles were incorporated into AZ31B magnesium alloy welded joints using the friction stir welding technique at five different stir zone volume fractions. The volume percentage of nano-SiC was varied from 0–20% in increments of 4%. Initially, the microstructure analyses of the V4, V8, and V12 welded joints were observed to be in good accordance with a homogeneous dispersion of nano SiC particles within the stir zone (SZ). Moreover, the particle’s agglomeration and large cluster size were found in the SZ due to insufficient heat generation of the specimen’s V16 and V20 during friction stir welding (FSW). Furthermore, the tensile and microhardness test was conducted, and the results indicate that the volume fractions increase along with the ultimate tensile strength and average microhardness, which increases up to 12% SiC addition (V12). With this effect, the fracture morphology was examined in the nano-composite joints that revealed a brittle fracture mode, which was observed in specimens V16 and V20, and the remaining was in the ductile fracture mode. From this investigation, a significant enhancement was found in the weld nugget zone that the tensile strength value of the V12 specimen was improved by 21% compared to the welded joint without SiC.

scholarly journals Influence of tool offsetting and base metal positioning on the material flow of AA5052-AA6061 dissimilar friction stir welding

2020 ◽  
Vol 14 (1) ◽  
pp. 6393-6402 ◽  
Author(s):  
Luqman Hakim Ahmad Shah ◽  
Abdelbaset Midawi ◽  
Scott Walbridge ◽  
Adrian Gerlich
Keyword(s):  
Mechanical Property ◽  
Friction Stir Welding ◽  
Material Flow ◽  
Base Material ◽  
Stir Zone ◽  
Base Metals ◽  
Friction Stir ◽  
Tool Offset ◽  
Dissimilar Friction Stir Welding ◽  
Property Characterization

This study examines dissimilar friction stir welding of AA5052-AA6061 aluminum alloys with varying tool offsets. The base metals were positioned and fixed at a slight diagonal positioning such that varying tool offset position from the centreline can also be varied along the length of the weld. After the fabrication process, microstructural and mechanical property characterization was subsequently conducted. The results show that, above a certain threshold for tool offset, incomplete consolidation (i.e. kissing bond defects) will occur. Regardless of the base material positioning, a zero tool offset shows optimum intermixing in the stir zone. EDX mapping confirms the presence of a distinct interface between both materials in the stir zone region. However, enhanced material intermixing and better elongation are observed when AA6061 alloy is positioned at the tool advancing side.

scholarly journals Shoulder Related Temperature Thresholds in FSSW of Aluminium Alloys

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4375
Author(s):  
David G. Andrade ◽  
Sree Sabari ◽  
Carlos Leitão ◽  
Dulce M. Rodrigues
Keyword(s):  
Heat Generation ◽  
Process Parameters ◽  
Rotational Speed ◽  
Aluminium Alloys ◽  
Spot Welding ◽  
Base Material ◽  
Main Process ◽  
Welding Temperature ◽  
Friction Stir ◽  
Tool Diameter

Friction Stir Spot Welding (FSSW) is assumed as an environment-friendly technique, suitable for the spot welding of several materials. Nevertheless, it is consensual that the temperature control during the process is not feasible, since the exact heat generation mechanisms are still unknown. In current work, the heat generation in FSSW of aluminium alloys, was assessed by producing bead-on-plate spot welds using pinless tools. Coated and uncoated tools, with varied diameters and rotational speeds, were tested. Heat treatable (AA2017, AA6082 and AA7075) and non-heat treatable (AA5083) aluminium alloys were welded to assess any possible influence of the base material properties on heat generation. A parametric analysis enabled to establish a relationship between the process parameters and the heat generation. It was found that for rotational speeds higher than 600 rpm, the main process parameter governing the heat generation is the tool diameter. For each tool diameter, a threshold in the welding temperature was identified, which is independent of the rotational speed and of the aluminium alloy being welded. It is demonstrated that, for aluminium alloys, the temperature in FSSW may be controlled using a suitable combination of rotational speed and tool dimensions. The temperature evolution with process parameters was modelled and the model predictions were found to fit satisfactorily the experimental results.

Optimization of friction stir welding parameters of dissimilar aluminium alloys 6061 and 5083 by using response surface methodology

2021 ◽  
pp. 095440622110058
Author(s):  
Sanjeev Verma ◽  
Vinod Kumar
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Tilt Angle ◽  
Feed Rate ◽  
Aluminium Alloys ◽  
Welded Joint ◽  
Welding Parameters ◽  
Friction Stir ◽  
Industrial Sectors ◽  
Tool Pin

Aluminium and its alloys are lightweight, corrosion-resistant, affordable and high-strength material and find wide applications in shipbuilding, automotive, constructions, aerospace and other industrial sectors. In applications like aerospace, marine and automotive industries, there is a need to join components made of different aluminium alloys, viz. AA6061 and AA5083. In this study friction stir welding (FSW) is used to join dissimilar plates made of AA6061-T6 and AA5083-O. The effect of varying tool pin profile, tool rotation speed, tool feed rate and tilt angle of the tool has been investigated on the tensile strength and percentage elongation of the welded joints. Box-Behkan design, with four input parameters and three levels of each parameter has been employed to decide the set of experimental runs. The regression models have been developed to investigate the influence of welding variables on the tensile strength and elongation of the welded joint. It is revealed that with the increase in welding parameters like tool rpm, tool feed rate and tilt angle of the tool, both the mechanical properties increase, reach a maximum level, followed by a decrease with further increase in the value of parameters. Amongst different types of tool pin profiles used, the FSW tool having straight cylindrical (SC) pin profile is found to yield the maximum strength and elongation of the welded joint for different combinations of welding parameters. Multiple response optimization indicates that the maximum UTS (135.83 MPa) and TE (4.35%) are obtained for the welded joint fabricated using FSW tool having SC pin profile, tilted at 1.11° and operating at tool speed and feed rate of 1568 rpm and 39.53 mm/min., respectively.

Stir zone material flow patterns during friction stir welding of heavy gauge AA5056 workpieces and stability of its mechanical properties

2021 ◽  
Vol 23 (4) ◽  
pp. 140-154
Author(s):  
Tatiana Kalashnikova ◽  
◽  
Vladimir Beloborodov ◽  
Kseniya Osipovich ◽  
Andrey Vorontsov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Elevated Temperatures ◽  
Thin Sheet ◽  
Stir Zone ◽  
Clear Correlation ◽  
Material Structure ◽  
Friction Stir ◽  
Significant Difference

Introduction. Friction stir welding and processing are almost identical processes of severe plastic deformation at elevated temperatures. These technologies differ mainly in the purpose of its use: the formation of a hardened surface layer or producing a welded joint. However, it is known that both during welding and during processing of heavy gauge workpieces temperature gradients occur. As a result, the conditions of adhesive interaction, material plastic flow, and the formation of the stir zone change as compared to thin-sheet workpieces with fundamentally different heat dissipation rates. In this connection, the purpose of the work is to determine the regularities of the structure formation and stability of the mechanical properties in different directions in the material of 35-mm-thick aluminum-magnesium alloy samples produced by friction stir welding/processing. Research Methodology. The technique and modes of friction stir welding and processing of AA5056 alloy workpieces with a thickness of 35 mm are described. Data on the equipment used for mechanical tests and structural research are given. Results and discussion. The data obtained show the excess mechanical properties of the processing zone material over the base metal ones in all studied directions. Material structure heterogeneities after friction stir welding/processing of heavy gauge workpieces have no determining effect on the stir zone properties. At the same time, there is no clear correlation between the tensile strength values and the load application direction, nor is there any significant difference in mechanical properties depending on the location of the samples inside the stir zone. The average ultimate tensile strength values in the vertical, transverse, and longitudinal directions are 302, 295 and 303 MPa, respectively, with the yield strength values of 155, 153 and 152 MPa, and the relative elongation of 27.2, 27.5, 28.7 %.

scholarly journals Research on the Friction Stir Welding of Sc-Modified AA2519 Extrusion

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1024 ◽  
Author(s):  
Robert Kosturek ◽  
Lucjan Śnieżek ◽  
Janusz Torzewski ◽  
Marcin Wachowski
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Base Material ◽  
Stir Zone ◽  
Welding Parameters ◽  
Friction Stir ◽  
Treated Condition ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
Fsw Parameters

The aim of this research was to investigate the effect of friction stir welding (FSW) parameters on microstructure and mechanical properties of Sc-modified AA2519 extrusion joints. The workpiece was welded by FSW in non-heat-treated condition with seven different sets of welding parameters. For each obtained joint macrostructure and microstructure observations were performed. Mechanical properties of joints were investigated using tensile test together with localization of fracture location. Joint efficiencies were established by comparing measured joints tensile strength to the value for base material. The obtained results show that investigated FSW joints of Sc-modified AA2519 in the non-heat-treated condition have joint efficiency within the range 87–95%. In the joints obtained with the lowest ratio of the tool rotation speed to the tool traverse speed, the occurrence of imperfections (voids) localized in the stir zone was reported. Three selected samples were subjected to further investigations consisting microhardness distribution and scanning electron microscopy fractography analysis. As the result of dynamic recrystallization, the microhardness of the base material value of 86 HV0.1 increased to about 110–125 HV0.1 in the stir zone depending on the used welding parameters. Due to lack of the strengthening phase and low strain hardening of used alloy the lack of a significantly softened zone was reported by both microhardness analysis and investigation of the fractured samples.

Study of Friction Stir Welding Technics and Weld Performance of Dissimilar 6063-3A21 Aluminum Alloys

2011 ◽  
Vol 299-300 ◽  
pp. 1095-1098 ◽  
Author(s):  
Lei Wang ◽  
Jian Jun Zhu ◽  
Wei Zhang ◽  
Xing Mei Feng ◽  
Zhan Ying Feng
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloys ◽  
Base Material ◽  
Post Weld Heat Treatment ◽  
Weld Strength ◽  
Welding Parameters ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys ◽  
Performance Results ◽  
Better Than

Several rotating rates and welding speeds were chosen to joint 6063/3A21 dissimilar aluminum alloys, tensile strength of the welds were measured to analyze effect of welding parameters on weld performance. Results show that tensile strength of the weld is better than the base material. Weld tensile strength will decrease under a too high or too low welding speed while effect of rotating rate on weld strength is relatively small. The weakest position is at heat affected zone at 3A21 side after T6 post weld heat treatment.

Improvement in Mechanical and Metallurgical Properties of Friction Stir Welded 6061-T6 Aluminum Alloys through Cryogenic Treatment

2019 ◽  
Vol 969 ◽  
pp. 490-495
Author(s):  
K. Tejonadha Babu ◽  
S. Muthukumaran ◽  
C.H. Bharat Kumar ◽  
C. Sathiya Narayanan
Keyword(s):  
Aluminum Alloys ◽  
Welded Joints ◽  
Cryogenic Treatment ◽  
Base Material ◽  
Cryogenic Cooling ◽  
Stir Zone ◽  
Welding Parameters ◽  
Cooling Rates ◽  
Friction Stir ◽  
Metallurgical Properties

An investigation has been made to improve the properties of the friction stir welded (FSW) 6061-T6 aluminum alloys. A cryogenic thermal treatment is developed for the joints during welding and its effects on mechanical and metallurgical properties, and precipitates are evaluated at various welding parameters. The friction stir welded joints with cryogenic treatment attained the better properties than the without cryogenic treatment. The improvement of properties was attributed to the refinement of grain size and to the introduction of a reduction in the softening region of the welded joints. Under cryogenic cooling rates, joints were experienced to the low temperature environments and faster cooling rates, which are contributed to enhance the hardness of the stir zone and heat affected zone regions and the formation of fine grain structure in the stir zone. The results indicated that the formation of finer grains of less than 5 µm in the stir zone, which is smaller than the joints of without cryogenic treatment. Subsequently, mechanical properties drastically improved and the joints achieved a maximum joint efficiency of 74% of the base material

Effect of Tool pin Profile and Axial Force on Tensile Behavior in Friction Stir Welding of Dissimilar Aluminum Alloys

2011 ◽  
Vol 415-417 ◽  
pp. 1140-1146 ◽  
Author(s):  
R. Palanivel ◽  
P. Koshy Mathews ◽  
M. Balakrishnan ◽  
I. Dinaharan ◽  
N. Murugan
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Axial Force ◽  
Aluminium Alloys ◽  
Welding Process ◽  
Fusion Welding ◽  
Friction Stir ◽  
Tool Pin Profile ◽  
Dissimilar Aluminum Alloys ◽  
Tool Pin

Aluminium alloys generally has low weldability by traditional fusion welding process. The development of the Friction Stir Welding (FSW) has provided an alternative improved way of producing aluminium joints, in a faster and reliable manner. FSW process has several advantages, in particular the possibility to weld dissimilar aluminium alloys. This study focuses on the behavior of tensile strength of dissimilar joints of AA6351-T6 alloy to AA5083-H111 alloy produced by friction stir welding was analysed. Five different tool pin profile such as Straight Square (SS), Tapered Square (TS), Straight Hexagon (SH), Straight Octagon (SO) and Tapered Octagon (TO) with three different axial force (1tonne, 1.5tonne, 2 tonne) have been used to weld the joints. The effect of pin profiles and axial force on tensile properties and material flow behaviour of the joint was analyzed and it was found that the straight square pin profile with 1.5 tonne produced better tensile strength then other tool pin profile and axial force.

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