Effect of Process Parameters on the Mechanical Properties of Friction Stir Welded Al-Li Alloy Butt Joints

2012 ◽  
Vol 155-156 ◽  
pp. 1096-1101
Author(s):  
D.D. Zhang ◽  
W.Q. Qu ◽  
Q. Meng ◽  
P. Chai ◽  
G.H. Luan ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Heat Input ◽  
Base Material ◽  
Welding Process ◽  
Weld Nugget ◽  
Tensile Fracture ◽  
Welding Parameters ◽  
Butt Joints ◽  
Obvious Effect ◽  
Friction Stir

Friction stir welding (FSW) is a new and promising welding process that can produce low-cost and high-quality joints of Al-Li alloy. In order to demonstrate the friction stir weldability of Al-Li alloy and determine optimum welding parameters, the effect of FSW welding parameters on the tensile properties of the Al-Li alloy butt joints has been studied in this paper. The results showed that, when the heat input increased, the ultimate strength and elongation of butt joints decreased. For the Al-Li alloy butt structure with the thickness of 2mm, the optimum parameters were the rotation speed of 600 rpm, the welding speed of 400mm/min, and the ultimate strength of butt structure was the maximum strength, arrived at 413MPa, equivalent to 83% that of the base material. Furthermore, it was found from the microstructural observation that, the welding parameters had obvious effect on the grain size of welded zone. As the heat input increasing, the grains of weld nugget and heat affected zone became larger accordingly. In addition, a special layered phenomenon appeared at tensile fracture surface, the tensile cracks initiated from the surface on welded zone near the thermomechanically affected zone(TMAZ) on the advancing side and then grew along the interface between the weld nugget and the TMAZ. The overall fracture mode was ductile - brittle hybrid fracture.

Mechanical Properties and Corrosion Resistance of Friction Stir Welded Dissimilar Aluminum Alloys 2219 to 5083

2015 ◽  
Vol 813-814 ◽  
pp. 203-207
Author(s):  
M. Koilraj ◽  
A. Sathesh Kumar ◽  
D.L. Belgin Paul ◽  
S.R. Koteswara Rao
Keyword(s):  
Base Material ◽  
Welding Process ◽  
Weld Nugget ◽  
Welding Parameters ◽  
General Corrosion ◽  
Test Results ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys ◽  
Shoulder Diameter ◽  
Mechanical Properties And Corrosion

In this paper, 6 mm thickness dissimilar aluminium alloys of 5083 (H321) and 2219 (O) butt joints were fabricated successfully by friction stir welding process. The quality joints were obtained for the welding parameters of 35 mm/min and 650 rpm with the shoulder diameter to pin diameter ratio as 3. Macrostructure study shows that the interface between the weld nugget and TMAZ is smooth and clear with a flow arm extending towards the top surface of the weld in the 2219 side. The boundary on the 5083 side between the weld nugget and the TMAZ was irregular. The obtained joint efficiency is around 92.57% based on the UTS of the softer material (AA2219). The tensile test results showed that the specimens failed in the heat affected zone of the softer base material 2219. The hardness values in the stirred zone are higher than the softer base material of alloy 2219. The friction stir welded dissimilar joint 2219-5083 exhibited better general corrosion characteristics than the 2219-2219 weld and 2219 base material.

Mechanical Behaviour of Al-Li Alloy Joints by Different Friction Stir Welding Parameters

2014 ◽  
Vol 1051 ◽  
pp. 799-807 ◽  
Author(s):  
Dan Dan Zhang ◽  
Wen Qing Qu ◽  
Qun Bo Lv ◽  
Yang Yang Liu ◽  
Wei Yan Li ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Base Material ◽  
Welding Process ◽  
Fatigue Properties ◽  
Welding Parameters ◽  
Fatigue Lifetime ◽  
Friction Stir ◽  
The Relationship ◽  
Microstructure And Mechanical Property ◽  
Made In

In this study, the Al-Li alloy plates were friction stir welded (FSW) at different welding parameters, and the effect of welding parameters on the hardness, tensile and fatigue properties of the butted and lapped FSWed joints were investigated. The experimental results showed that the ultimate strength and elongation of butted joints decreased as the heat input increasing, and the maximum ultimate strength of the joints was equivalent to 83% that of the base material. By comparison of the heat inputs during welding process at different parameter combinations, the relationship between the microstructure and mechanical property of FSWed joints was established. For the overlapped welds made in 2mm thick plates of Al-Li-S4 and 2099 alloys, the hooking defect was a typical and inevitable defect appearing on the TMAZ of both advancing and retreating sides, which would adversely damage the mechanical properties of overlapped joints. Furthermore, the length of pin significantly affected the tensile property of overlapped joints, when the length of pin varies from 2.8mm to 2.5mm, the ultimate strength increased 14% to 20%. In addition, the fatigue lifetime of overlapped joints was lower than that of butted joints and base metal.

Mechanical Characterization of AA2024-T3 FSWed Butt Joints

2013 ◽  
Vol 753-755 ◽  
pp. 431-434 ◽  
Author(s):  
Pierpaolo Carlone ◽  
Gaetano S. Palazzo
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characterization ◽  
Base Material ◽  
Welding Process ◽  
Butt Joints ◽  
Influence Of Process Parameters ◽  
Rotating Speed ◽  
Friction Stir ◽  
Process Heat

In recent years friction stir welding process has received a great deal of attention from the transport industry. During the process, heat generation and material stirring induce significant microstructural alteration in the base material, affecting the properties of the welded assembly. In this paper the influence of process parameters, namely rotating speed and welding speed, on mechanical properties of AA2024-T3 friction stir butt welds is experimentally investigated. An increase of the yield stress has been found decreasing the heat input, while an opposite variation was measured for the elongation.

Fatigue Crack Growth on FSW AA2024-T3 Aluminum Joints

2012 ◽  
Vol 498 ◽  
pp. 126-138 ◽  
Author(s):  
Pedro Miguel Guimarães Pires Moreira ◽  
Paulo Manuel Salgado Tavares de Castro
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Solid State ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Base Material ◽  
Welding Process ◽  
Butt Joints ◽  
Friction Stir

Friction stir welding (FSW) is a solid-state joining process which emerged as an alternative technology to join high strength alloys that were difficult to weld with conventional techniques, [1]. Developments of this technique are being driven by aeronautic, aerospace and railway industries. An advantage of this joining technique is its low heat input when compared with arc welding processes. This feature allows the achievement of high mechanical properties, low distortion and low residual stresses, [2]. Also, since it is a solid-state welding process, hydrogen cracking or heat affected zone (HAZ) softening phenomena are limited. This paper presents a study of fatigue crack growth behaviour of friction stir welded butt joints of AA2024-T3, aluminium commonly used in riveted aeronautic fuselage structures. Crack growth studies are often carried out using uniform thickness joints, ASTM E647 [3]. Nevertheless, for some applications there is a need to join components with different thicknesses, which, under certain limits, can be welded using FSW. Crack growth tests on these joints are not standard. The present study concerns butt joints made using two plates with different thicknesses, 3.8mm and 4.0mm. The joints’ mechanical behaviour was studied performing static (tensile) and fatigue tests. The fatigue crack growth rate of cracks growing in different zones of the welded joint (nugget, heat affected zone - HAZ) and in base material was analysed. The microhardness profile was assessed in order to analyse the influence of the welding process in each weld zone. Further to higher static properties, welded joints present lower crack growth rate when compared with its base material.

Effect of Welding Parameters on Defects and Fracture Behavior of Friction Stir Welded 2195-T8 Al-Li Alloy Joints

2018 ◽  
Vol 913 ◽  
pp. 182-189
Author(s):  
Yang Wu ◽  
Hua Mao ◽  
Qing Bo Yang ◽  
Zhi Qing Zhang
Keyword(s):  
Friction Stir Welding ◽  
Heat Input ◽  
Fracture Behavior ◽  
Sudden Change ◽  
Vertical Direction ◽  
Welding Parameters ◽  
Hardness Profile ◽  
Butt Joints ◽  
Friction Stir ◽  
Thermal Affected Zone

In this work, the ratio of rotation rate to advancing speed was fixed to 10 to fabricate friction stir welding (FSW) butt joints of 2195 - T8 plates with 7.5 mm in thickness. The results revealed that the heat input of joints along the vertical direction varied with the welding parameters though these parameters had a same ratio. 500-50 and 600-60 joints failed in the thermal affected zone and thermal mechanical affected zone (TAZ/TMAZ), while other joints all failed in stirred zone (SZ). The hardness profile across the joints showed a similar W shape, while the hardness in bottom area increased with the increasing of parameters. Lazy S and kissing - bond defects appeared in all of these joints, and over - burn defect was also found in 1000-100 joint. It is concluded that the heat input distribution gradient during FSW across the joints becomes non-uniform and a sudden change between upper and lower areas even occurs.

scholarly journals Friction stir welding of new electronic packaging materials SiCp/Al composite with T-joint

2018 ◽  
Vol 38 (3) ◽  
pp. 352-359
Author(s):  
Zeng Gao ◽  
Jianguang Feng ◽  
Huanyu Yang ◽  
Jukka Pakkanen ◽  
Jitai Niu
Keyword(s):  
Friction Stir Welding ◽  
Base Material ◽  
Welding Process ◽  
Experimental Results ◽  
Homogeneous Distribution ◽  
Welding Parameters ◽  
Matrix Composites ◽  
Friction Stir ◽  
Lower Temperature ◽  
Gas Tightness

Using friction stir welding, the electronic container box and lid made from aluminium matrix composites with reinforcement of SiC particle (15 vol% SiCp/Al-MMCs) was welded successfully with T-joint. The temperature distribution of box during the process, mechanical property and microstructure of the joint as well as gas tightness of welded box was investigated. The experimental results indicated that the satisfactory T-joint can be obtained under appropriate friction stir welding parameters. During the welding process, the bottom center, which was used to place the electronic component, reached a quite lower temperature of 100°C. That can ensure safety of components in the box. After the welding process, the microstructure in stir zone was better than in base material due to the refining and homogeneous distribution of the SiC particles. The experimental results showed that the electronic container box after friction stir welding had gas tightness. The He-leakage rate was under 10-8 Pa•m3/s.

Feasibility study of welding dissimilar Advanced and Ultra High Strength Steels

2020 ◽  
Vol 59 (1) ◽  
pp. 54-66
Author(s):  
Francois Njock Bayock ◽  
Paul Kah ◽  
Antti Salminen ◽  
Mvola Belinga ◽  
Xiaochen Yang
Keyword(s):  
Heat Input ◽  
High Strength Steel ◽  
Gas Metal Arc Welding ◽  
Base Material ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Hardness Test ◽  
Welding Parameter ◽  
Welding Parameters

AbstractThis study concerns the weldability of dissimilar Ultra high-strength steel (UHSS) and advanced high-strength steel (AHSS), which is used in the modern machine industry. The materials offered superior strength as well as relatively low weight, which reduces microstructure contamination during a live cycle. The choice of the welding process base of the base material (BM) and welding parameters is essential to improve the weld joint quality. S700MC/S960QC was welded using a gas metal arc welding (GMAW) process and overmatched filler wire, which was performed using three heat input (7, 10, and 15 kJ/cm). The weld samples were characterized by a Vickers-hardness test, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The test reveals a decrease of softening areas in the HAZ and the formation of the stable formation of Bainite-Ferrite for S700MC and Bainite-martensite for S960QC when the heat input of 10 kJ/cm is used. It is recommended to use the GMAW process and Laser welding (Laser beam-MIG), with an optimal welding parameter, which will be achieved a high quality of manufacturing products.

Influence of Friction Stir Welding Parameters on the Mechanical Properties of EN AW-7075 Weld Joints

2016 ◽  
Vol 835 ◽  
pp. 210-215
Author(s):  
Máté Nagy ◽  
Mária Behúlová
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Ultimate Strength ◽  
Base Material ◽  
High Strength ◽  
Welding Parameters ◽  
Micro Hardness ◽  
Friction Stir ◽  
Weld Joints ◽  
Welding Processes

The paper deals with the friction stir welding (FSW) of the high strength EN AW 7075-T651 aluminium alloy with the aim to analyze the influence of welding parameters on the mechanical properties of Al-weld joints. FSW represents relatively novel solid-state technology of material joining which can be successfully applied for welding of several metallic alloys including the high-strength aluminium alloys that are hard to weld by conventional fusion welding processes. In cooperation with VÚZ - PI SR Bratislava, nine experimental weld joints of samples with dimensions of 300 × 150 × 10 mm were prepared using the welding machine of the FSW-LM-060 type and different parameters of welding – the welding speed from 60 to 120 mm/min and the tool rotation rate from 600 to 1000 rpm in clockwise direction. The quality of weld joints was evaluated by static tensile tests and micro-hardness measurements. According to obtained results of tensile testing, the average values of ultimate strength of weld joints are by 32.2 % lower comparing with the ultimate strength of the base material. On the other hand, the ductility increased by 7.2 %. The highest micro-hardness of weld joints at the level of 129 HV was measured in thermo-mechanically affected zone on the retreating side.

An investigation into the effect of welding parameters on fatigue crack growth rate and fracture toughness in friction stir welded copper sheets

2015 ◽  
Vol 232 (3) ◽  
pp. 191-203 ◽  
Author(s):  
Ali Alavi Nia ◽  
Ali Shirazi
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Heat Affected Zone ◽  
Base Material ◽  
Welding Process ◽  
Stir Zone ◽  
Welding Parameters ◽  
Friction Stir

In the present study, the effect of various factors of friction stir welding including rotational and traverse speeds of tool and in fact, the amount of the heat transferred within welding was evaluated on the resistance to fatigue crack growth and fracture toughness in different zones of welding copper sheets. In order to better assess these two properties, other mechanical properties such as tensile strength and hardness were also studied and the microstructure of different zones of welds was investigated using optic and electron microscopies. By doing this study, it became clear that the less the heat transferred to the plunging during the welding process, the better properties the resulting welds will have which well justifies the use of cooling in this study. Transferring heat to plunging causes the growth of grains in various zones and can cause the fatigue crack growth in heat-affected zone to increase averagely about 4.2 times the base material for different Δ K. In contrast, the occurrence of dynamic recrystallization in the stir zone as well as fragmentizing and alignment of grains in this zone can increase the resistance to fatigue crack growth up to 9-fold the resistance of the base material. The other interesting result of this study was that although the properties of stir zone improve by increasing the number of welding passes, the properties of its weakest zone i.e. the heat-affected zone will decline.

Microstructural and Mechanical Characterization of Friction Stir Welded- 1050 Aluminium Alloy

2009 ◽  
Vol 83-86 ◽  
pp. 1173-1181
Author(s):  
Magdy M. El Rayes ◽  
Ehab A. El-Danaf ◽  
Mahmoud S. Soliman
Keyword(s):  
Welding Speed ◽  
Rotational Speed ◽  
Welding Process ◽  
Grain Structure ◽  
Weld Nugget ◽  
Frictional Heat ◽  
Welding Parameters ◽  
Work Piece ◽  
Tool Rotational Speed ◽  
Friction Stir

Friction stir welding (FSW) is a fairly recent technique that utilizes a non-consumable rotating welding tool to generate frictional heat and plastic deformation at the welding location in the continuously-fed work piece. In the present investigation this welding process is applied to join 1050 cold-rolled aluminium plates. The effects of varying the welding parameters namely welding speed [56, 90 and 140 mm/min] and tool rotational speed [850 and 1070 rpm] on the mechanical and microstructural properties were studied. Vickers micro hardness results across the weldment showed that the weld nugget hardness is dependant upon the welding speed and the tool rotational speed. Increasing the welding speed at 850 rpm reduced the hardness at the weld nugget, whereas, at 1070 rpm the weld nugget hardness merely did not change. However, the hardness achieved at 850 rpm was constantly higher than that achieved with 1070 rpm irrespective to welding speeds. In the same fashion, the yield and ultimate strengths of the joints were influenced by varying the welding parameters. Increasing the welding speed at 850 rpm reduced both strengths whereas; at 1070 rpm they were almost unchanged. Microstructural study showed that the weld region is composed of unaffected base metal and the stir zoned [weld nugget] which is characterised by a fine equiaxed grain structure. Increasing the welding speed at constant tool rotational speed has caused a slight refinement in the weld nugget's grain size, whereas, decreasing the rotational speed has also led to weld nugget grain refinement.

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