Effect of Welding Speeds on Mechanical Properties of Level Compensation Friction Stir Welded 6061-T6 Aluminum Alloy

2016 ◽  
Vol 35 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Quan Wen ◽  
Yumei Yue ◽  
Shude Ji ◽  
Zhengwei Li ◽  
Shuangsheng Gao
Keyword(s):  
Aluminum Alloy ◽  
Welding Speed ◽  
Weld Zone ◽  
Base Material ◽  
Tensile Fracture ◽  
Tool Rotational Speed ◽  
Friction Stir ◽  
Fracture Position ◽  
Transverse Tensile ◽  
Equal Thickness

AbstractIn order to eliminate the flash, arc corrugation and concave in weld zone, level compensation friction stir welding (LCFSW) was put forward and successfully applied to weld 6061-T6 aluminum alloy with varied welding speed at a constant tool rotational speed of 1,800 rpm in the present study. The glossy joint with equal thickness of base material can be attained, and the shoulder affected zone (SAZ) was obviously reduced. The results of transverse tensile test indicate that the tensile strength and elongation reach the maximum values of 248 MPa and 7.1% when the welding speed is 600 mm/min. The microhardness of weld nugget (WN) is lower than that of base material. The tensile fracture position locates at the heat affected zone (HAZ) of the advancing side (AS), where the microhardness is the minimum. The fracture surface morphology represents the typical ductile fracture.

scholarly journals Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4211 ◽  
Author(s):  
Anton Naumov ◽  
Iuliia Morozova ◽  
Evgenii Rylkov ◽  
Aleksei Obrosov ◽  
Fedor Isupov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Welding Speed ◽  
Welded Joints ◽  
High Speed ◽  
Structural Characteristics ◽  
Tensile Fracture ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Aluminum Sheets

The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations.

Effects of welding speeds on the microstructural and mechanical properties of AZ91D Mg alloy by friction stir welding

2020 ◽  
Vol 11 (6) ◽  
pp. 769-782 ◽  
Author(s):  
Nagabhushan Kumar Kadigithala ◽  
Vanitha C
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Welding Speed ◽  
Base Material ◽  
Welding Parameters ◽  
Content Type ◽  
Friction Stir ◽  
Az91d Magnesium Alloy ◽  
Transverse Tensile

PurposeThe main purpose of the present work is to evaluate, the microstructural and mechanical properties of friction stir welded plates of AZ91D magnesium alloy with 3 mm thickness, and to determine the optimum range of welding conditions.Design/methodology/approachMicrostructure and fractographic studies were carried out using scanning electron microscopy (SEM). Vickers micro hardness test was performed to evaluate the hardness profile in the region of the weld area. The phases in the material were confirmed by X-Ray diffraction (XRD) analysis. Transverse tensile tests were conducted using universal testing machine (UTM) to examine the joint strength of the weldments at different parameters.FindingsMetallographic studies revealed that each zone shown different lineaments depending on the mechanical and thermal conditions. Significant improvement in the hardness was observed between the base material and weldments. Transverse tensile test results of weldments had shown almost similar strength that of base material regardless of welding speed. Fractographic examination indicated that the welded specimens failed due to brittle mode fracture. Through these studies it was confirmed that friction stir welding (FSW) can be used for the welding of AZ91D magnesium alloy.Research limitations/implicationsIn the present study, the welding speed varied from 25 mm/min to 75 mm/min, tilt angle varied from 1.5° to 2.5° and constant rotational speed of 500 rpm.Practical implicationsMagnesium and aluminum based alloys which are having high strength and low density, used in automotive and aerospace applications can be successfully joined using FSW technique. The fusion welding defects can be eliminated by adopting this technique.Originality/valueLimited work had been carried out on the FSW of magnesium based alloys over aluminum based alloys. Furthermore, this paper analyses the influence of welding parameters over the microstructural and mechanical properties.

Vertical Compensation Friction Stir Welding of 6061-T6 Aluminum Alloy

2016 ◽  
Vol 35 (8) ◽  
pp. 843-851 ◽  
Author(s):  
Shude Ji ◽  
Xiangchen Meng ◽  
Jingwei Xing ◽  
Lin Ma ◽  
Shuangsheng Gao
Keyword(s):  
Adverse Effect ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Rotational Velocity ◽  
Weld Zone ◽  
Strengthening Effect ◽  
Fracture Surface Morphology ◽  
Friction Stir

AbstractVertical compensation friction stir welding (VCFSW) was proposed in order to solve the adverse effect caused by a big gap at the interface between two welded workpieces. VCFSW was successfully applied to weld 6061-T6 aluminum alloy with the thickness of 4 mm, while 2024-T4 aluminum alloy was selected as a rational compensation material. The results show that VCFSW is difficult to get a sound joint when the width of strip is no less than 1.5 mm. Decreasing the welding speed is beneficial to break compensation strip into pieces and then get higher quality joint. When the width of strip is 1 mm, the tensile strength and elongation of joint at the welding speed of 50 mm/min and rotational velocity of 1,800 rpm reach the maximum values of 203 MPa and 5.2%, respectively. Moreover, the addition of 2024-T4 alloy plays a strengthening effect on weld zone (WZ) of VCFSW joint. The fracture surface morphology of joint consisting of amounts of dimples exhibits ductile fracture.

Nonuniformity of Mechanical Property in the Weld Zone of Friction Stir Welded 7050 Aluminum Alloy Joint

2011 ◽  
Vol 189-193 ◽  
pp. 3560-3563
Author(s):  
Yu Wen Tian ◽  
Fei Xu ◽  
Wen Ya Li ◽  
Zhong Bin Tang
Keyword(s):  
Mechanical Property ◽  
Aluminum Alloy ◽  
Elastic Modulus ◽  
Weld Zone ◽  
Base Material ◽  
Weld Nugget ◽  
Second Phase ◽  
Nugget Zone ◽  
Friction Stir ◽  
7050 Aluminum Alloy

The distribution of mechanical property in the weld zone of friction stir welded 7050 aluminum alloy joint along the plane perpendicular to the welding direction was experimentally investigated by the non-contact measurement method. The results show that the elastic modulus presents a W-shape distribution across the weld zone. The elastic modulus in the weld nugget zone is increased due to the grain refinement. In addition, the elastic modulus in the advancing side is slightly less than that in the retreating side possibly because of the relatively higher temperature in the advancing side during the welding process. The strength in the vicinity of weld center is decreased while the ductility is enhanced. The tensile strength and yield strength in the weld nugget zone and thermo-mechanically affected zone are significantly decreased while the elongation is increased due to the change of strengthening mechanism. In the heat affected zone the strength is decreased compared to the base material because the second phase grows up.

Friction Stir Lap Joining of AC4C Cast Aluminum Alloy and Zinc-Coated Steel

2008 ◽  
Vol 580-582 ◽  
pp. 371-374 ◽  
Author(s):  
Y.C. Chen ◽  
T. Komazaki ◽  
Y.G. Kim ◽  
Takuya Tsumura ◽  
Kazuhiro Nakata
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Intermetallic Compounds ◽  
Welding Speed ◽  
Base Material ◽  
Cast Aluminum Alloy ◽  
Coated Steel ◽  
Cast Aluminum ◽  
Friction Stir ◽  
Zinc Coated Steel

AC4C cast aluminum alloy and zinc-coated steel were friction stir lap welded, and the microstructures and mechanical properties of the joints were examined and analyzed. Experimental results show that the welding speeds have a significant effect on the tensile properties and fracture locations of the joints at a rotational speed of 1500 rpm. When the welding speed is higher than 60 mm/min, the joints fracture in the zinc-coated steel base material and the tensile strength is equal to that of the zinc-coated steel; when the welding speed is lower than 60 mm/min, the joints fracture in the interface and the shear strength is about 50 MPa. The change of the fracture locations is attributed to the presence of large quantity intermetallic compounds adjacent to the interface of the joints. The composition and formation mechanism of the intermetallic compounds and its effect on the mechanical properties of the joints were discussed.

scholarly journals Springback of Friction Stir Welded Sheets Made of Aluminium Grades during V-Bending: An Experimental Study

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
B. Durga Rao ◽  
R. Ganesh Narayanan
Keyword(s):  
Yield Strength ◽  
Young’S Modulus ◽  
Welding Speed ◽  
Rotational Speed ◽  
Young's Modulus ◽  
Weld Zone ◽  
Base Material ◽  
Strain Hardening Exponent ◽  
Friction Stir ◽  
Shoulder Diameter

The main aim of the present work is to study the effect of shoulder diameter, rotational speed, and welding speed on the springback performance of friction stir welded sheets. The friction stir welded sheets are made by welding 6061T6 to 5052H32, and 6061T6 to 6061T6. The springback has been evaluated after V-bending of welded sheets, involving pure bending. The relation between springback and weld zone properties like yield strength, Young’s modulus, yield strength to Young’s modulus ratio, and strain hardening exponent is identified. It is found that, with increase in shoulder diameter, rotational speed, and welding speed, the springback of friction stir welded sheets has reduced, and is independent of the material combinations. The relation between springback and weld properties change coincides with existing knowledge about springback. The friction stir welded sheets show better springback performance as compared to 6061T6 base material, but inferior to 5052H32 base material. By reducing the punch nose radius, the springback of friction stir welded sheets can be minimized. It is also concluded that, by proper tailoring of Al grades, and by alteration of weld zone properties through friction stir welding, the springback of friction stir welded sheets can be reduced considerably.

Improvement in Fatigue Strength of Friction Stir Welded Aluminum Alloy Plates by Laser Peening

2014 ◽  
Vol 891-892 ◽  
pp. 969-973 ◽  
Author(s):  
Yuji Sano ◽  
Kiyotaka Masaki ◽  
Keiichi Hirota
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Fatigue Testing ◽  
Large Deviation ◽  
Fatigue Cracks ◽  
Weld Zone ◽  
Base Material ◽  
Fatigue Properties ◽  
Laser Peening ◽  
Friction Stir

Plane bending fatigue testing was performed to study the fatigue properties of friction stir welded (FSW) 3 mm thick AA6061-T6 aluminum alloy plates. Fatigue cracks propagated with bends and curves on the specimens, showing large deviation from a linear line. This might be reflecting the material flow and microstructure in the weld zone. The fatigue strength of the unwelded base material (BM) was 110 MPa at 107 cycles and FSW deteriorated it to 90 MPa. However, laser peening (LP) restored the degraded fatigue strength up to 120 MPa which is higher than that of the BM.

Investigation on the Corrosion Effect of Friction Stir Welded AA2024 T3 Aluminum Alloy Joints

2012 ◽  
Vol 525-526 ◽  
pp. 129-132 ◽  
Author(s):  
Yu E Ma ◽  
Zhen Qiang Zhao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminum Alloy ◽  
Welded Joint ◽  
Weld Zone ◽  
Base Material ◽  
Localized Corrosion ◽  
Aircraft Structure ◽  
Friction Stir ◽  
Scanning Electron

Before friction stir welded integral panels are used in main aircraft structure, the corrosion behavior of welded joint need to be studied in detail. 2024 T3 samples were designed and welded by friction stir welding; the microstructure crossing the weld zone was observed by scanning electron microscopy (SEM), the feature of different zones (base material, thermo-mechanical affected zone, nugget) was seen; the corrosion testing in NaCl smoking box was carried out, and microstructure was observed after corrosion, localized corrosion predominantly occurs in the thermo-mechanical affected zone.

scholarly journals Mechanical and Microstructural Characterization of Friction Stir Welded SiC and B4C Reinforced Aluminium Alloy AA6061 Metal Matrix Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3110
Author(s):  
Kaveripakkam Suban Ashraff Ali ◽  
Vinayagam Mohanavel ◽  
Subbiah Arungalai Vendan ◽  
Manickam Ravichandran ◽  
Anshul Yadav ◽  
...  
Keyword(s):  
Wear Rate ◽  
Aluminium Alloy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Weld Zone ◽  
Base Material ◽  
Matrix Composites ◽  
Wear Properties ◽  
Friction Stir ◽  
Behavioural Aspects

This study focuses on the properties and process parameters dictating behavioural aspects of friction stir welded Aluminium Alloy AA6061 metal matrix composites reinforced with varying percentages of SiC and B4C. The joint properties in terms of mechanical strength, microstructural integrity and quality were examined. The weld reveals grain refinement and uniform distribution of reinforced particles in the joint region leading to improved strength compared to other joints of varying base material compositions. The tensile properties of the friction stir welded Al-MMCs improved after reinforcement with SiC and B4C. The maximum ultimate tensile stress was around 172.8 ± 1.9 MPa for composite with 10% SiC and 3% B4C reinforcement. The percentage elongation decreased as the percentage of SiC decreases and B4C increases. The hardness of the Al-MMCs improved considerably by adding reinforcement and subsequent thermal action during the FSW process, indicating an optimal increase as it eliminates brittleness. It was seen that higher SiC content contributes to higher strength, improved wear properties and hardness. The wear rate was as high as 12 ± 0.9 g/s for 10% SiC reinforcement and 30 N load. The wear rate reduced for lower values of load and increased with B4C reinforcement. The microstructural examination at the joints reveals the flow of plasticized metal from advancing to the retreating side. The formation of onion rings in the weld zone was due to the cylindrical FSW rotating tool material impression during the stirring action. Alterations in chemical properties are negligible, thereby retaining the original characteristics of the materials post welding. No major cracks or pores were observed during the non-destructive testing process that established good quality of the weld. The results are indicated improvement in mechanical and microstructural properties of the weld.

Fatigue crack paths and properties in A356-T6 aluminum alloy microstructurally modified by friction stir processing under different conditions

2015 ◽  
Author(s):  
A. Tajiri ◽  
Y. Uematsu ◽  
T. Kakiuchi ◽  
Y. Suzuki
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Crack Initiation ◽  
Friction Stir Processing ◽  
Casting Defects ◽  
Processing Conditions ◽  
Tool Rotational Speed ◽  
Crack Initiation And Propagation ◽  
Friction Stir ◽  
Initiation And Propagation

A356-T6 cast aluminum alloy is a light weight structural material, but fatigue crack initiates and propagates from a casting defect leading to final fracture. Thus it is important to eliminate casting defects. In this study, friction stir processing (FSP) was applied to A356-T6, in which rotating tool with probe and shoulder was plunged into the material and travels along the longitudinal direction to induce severe plastic deformation, resulting in the modification of microstructure. Two different processing conditions with low and high tool rotational speeds were tried and subsequently fully reversed fatigue tests were performed to investigate the effect of processing conditions on the crack initiation and propagation behavior. The fatigue strengths were successfully improved by both conditions due to the elimination of casting defects. But the lower tool rotational speed could further improve fatigue strength than the higher speed. EBSD analyses revealed that the higher tool rotational speed resulted in the severer texture having detrimental effects on fatigue crack initiation and propagation resistances.

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