Influence of TiO2 Particle on the Friction Stir Welding of 7075 Al Alloy

In this study, 2A14-T4 Al-alloy T-joints were prepared via stationary shoulder friction stir welding (SSFSW) technology where the stirring pin’s rotation speed was set as different values. In combination with the numerical simulation results, the macro-forming, microstructure, and mechanical properties of the joints under different welding conditions were analyzed. The results show that the thermal cycle curves in the SSFSW process are featured by a steep climb and slow decreasing variation trends. As the stirring pin’s rotation speed increased, the grooves on the weld surface became more obvious. The base and rib plates exhibit W- or N-shaped hardness distribution patterns. The hardness of the weld nugget zone (WNZ) was high but was lower than that of the base material. The second weld’s annealing effect contributed to the precipitation and coarsening of the precipitated phase in the first weld nugget zone (WNZ1). The hardness of the heat affect zone (HAZ) in the vicinity of the thermo-mechanically affected zone (TMAZ) dropped to the minimum. As the stirring pin's rotation speed increased, the tensile strengths of the base and rib plates first increased and then dropped. The base and rib plates exhibited ductile and brittle/ductile fracture patterns, respectively.

Download Full-text

Immersed friction stir welding of ultrafine grained accumulative roll-bonded Al alloy

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2010.05.007 ◽

2010 ◽

Vol 31 (10) ◽

pp. 4786-4791 ◽

Cited By ~ 29

Author(s):

M. Hosseini ◽

H. Danesh Manesh

Keyword(s):

Friction Stir Welding ◽

Al Alloy ◽

Friction Stir ◽

Ultrafine Grained

Download Full-text

Thermo-mechanical analysis of linear welding stage in friction stir welding - influence of welding parameters

Thermal Science ◽

10.2298/tsci210216186v ◽

2021 ◽

pp. 186-186

Author(s):

Darko Veljic ◽

Marko Rakin ◽

Aleksandar Sedmak ◽

Nenad Radovic ◽

Bojan Medjo ◽

...

Keyword(s):

Friction Stir Welding ◽

Heat Generation ◽

Welding Speed ◽

Reaction Force ◽

Material Model ◽

Element Model ◽

Welding Parameters ◽

Al Alloy ◽

Friction Stir ◽

Fsw Parameters

The influence of friction stir welding (FSW) parameters on thermo-mechanical behaviour of the material during welding is analysed. An aluminium alloy is considered (Al 2024 T351), and different rotating speed and welding speed are applied. Finite element model consists of the plate (Al alloy), backing plate and welding tool, and it is formed and solved in software package Simulia Abaqus. The influence of the welding conditions on material behaviour is taken into account by application of the Johnson-Cook material model. The rotation of the tool affects the results: if increased, it contributes to an increase of friction-generated heat intensity. The other component of the generated heat, the plastic deformation of the material, is negligibly changed. When the welding speed is increased, the intensity of friction-generated heat decreases, while the heat generation due to plastic deforming increases. Combined, these two effects cause small change of the total heat generation. For the same welded joint length, the plate welded by lower speed will be heated more intensively. The changes of the heat generation influence both the temperature field and reaction force, which are also considered.

Download Full-text

Friction Stir Welding with Low-Medium-High Tool Travel Speed of 0.95 Mg-Al-Alloy and Pure Copper: Electrochemical and Surface Studies

10.20944/preprints201812.0039.v1 ◽

2018 ◽

Author(s):

Neetesh Soni ◽

Ambrish Singh

Keyword(s):

Friction Stir Welding ◽

Process Parameters ◽

Pure Copper ◽

Travel Speed ◽

Localized Corrosion ◽

Al Alloy ◽

Kelvin Probe ◽

Friction Stir ◽

Surface Optical ◽

Joining Process

The aim of this work is to assess the influence of Friction Stir Welding (FSW), process parameters, optimized tool traveling speed, and corrosion resistance of the 0.95 Mg-Al-alloy and pure copper weldment. Samples of aluminum-copper with and without deformation were characterized to investigate the metallurgical effects created during the welding deformation process. Effect of process parameters on microstructure and corrosion rate have been investigated for all the samples. All the electrochemical and polarization tests were done in 3.5 wt.% NaCl solution. Scanning Kelvin Probe (SKP) was done to detect the localized corrosion on the surface. Optical micrography observation indicated that the primary α-Al phase, which was formed during solidification can effectively limit the growth of Cu9Al4 phase. Finer acicular α-Al precipitates were observed in CuAl matrix during joining process that tends to coarser with the increase in tools travel speed. The electrochemical and polarization results showed that among all the tool travelling speed the specimen joined at tool travelling speed of 40 mm/min shows the best non-corrosive property.

Download Full-text

Effect of double-sided friction stir welding on the mechanical and microstructural characteristics of AA5754 aluminium alloy

Materials Testing ◽

10.1515/mt-2021-0009 ◽

2021 ◽

Vol 63 (9) ◽

pp. 829-835

Author(s):

Sare Çelik ◽

Fatmagül Tolun

Keyword(s):

Friction Stir Welding ◽

Al Alloys ◽

Fusion Welding ◽

Welding Parameters ◽

Al Alloy ◽

Test Results ◽

Feeding Rates ◽

Microstructural Characteristics ◽

Friction Stir ◽

Tool Tilt Angle

Abstract AA5754Al alloy is widely used in industry. However, as in the case of all Al alloys, the 5xxx series Al alloys cannot be easily joined through fusion welding techniques. To address this problem, in this study, the effect of double-sided friction stir welding at various tool rotational speeds (450, 710, and 900 rpm), feeding rates (40, 50, and 80 mm × min-1), and tool tilt angles (0°, 1°, 2°) on the welding parameters and mechanical and microstructural characteristics of AA5754 Al alloy was determined. Tensile strength tests and microhardness tests were performed to examine the mechanical properties of the welded specimens. The microstructures of the welded zone were examined by obtaining optical microscopy and scanning electron microscopy images. The tensile test results indicated that the specimens exhibited the highest welding performance of 95.17 % at a tool rotational speed, feed rate, and tool tilt angle of 450 rpm, 50 mm × min-1 and 1°, respectively.

Download Full-text

Formation Investigation of Intermetallic Compounds of Thick Plate Al/Mg Alloys Joint by Friction Stir Welding

Materials ◽

10.3390/ma12172661 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2661 ◽

Cited By ~ 5

Author(s):

Yang Xu ◽

Liming Ke ◽

Yuqing Mao ◽

Qiang Liu ◽

Jilin Xie ◽

...

Keyword(s):

Diffusion Coefficient ◽

Friction Stir Welding ◽

Intermetallic Compounds ◽

Thick Plate ◽

Mg Alloys ◽

Diffusion Reaction ◽

Formation Mechanisms ◽

Phase Identification ◽

Al Alloy ◽

Friction Stir

5A06 Aluminum (Al) alloy and AZ31B magnesium (Mg) alloy with 20 mm thickness were successfully butt joined by friction stir welding. In order to control the composition of Al and Mg alloys along thickness direction, an inclined butt joint was designed in this study. The microstructure and phase identification at the interface of Al/Mg joints were examined using scanning electron microscopy with an energy-dispersive spectroscopy and Micro X-ray diffraction. The results indicated that there were two different formation mechanisms of intermetallic compounds at the interface of thick plate Al/Mg joint. The first was constitutional liquation, and eutectic structure consisting of Al12Mg17 and Mg solid solution existed at the top and upper-middle of the Mg side interface. The second was diffusion reaction, and the two sub-layers of Al12Mg17 and Al3Mg2 formed at the lower middle and bottom of the Mg side interface. In addition, the diffusion thickness values of Al12Mg17 and Al3Mg2 layers decreased gradually from the lower middle to bottom of the Mg side interface. As the position changes from the middle to the bottom near the Mg side interface, the diffusion coefficient of Al3Mg2 phase rapidly decreases from 3.14 × 10−12 m2/s to 6.9 × 10−13 m2/s and the diffusion coefficient of Al12Mg17 phase decreases from 6.8 × 10−13 m2/s to 1.5 × 10−13 m2/s.

Download Full-text

Interdiffusion Behavior in γ-Phase U-Mo Alloy versus Al-6061 Alloy Couples Fabricated by Friction Stir Welding

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.266.131 ◽

2007 ◽

Vol 266 ◽

pp. 131-148 ◽

Cited By ~ 11

Author(s):

Dennis D. Keiser

Keyword(s):

Friction Stir Welding ◽

Research Reactor ◽

Metastable Phase ◽

Al Alloy ◽

Friction Stir ◽

Point Analysis ◽

Interdiffusion Process ◽

Composition Profiles ◽

Point To Point ◽

The Stability

To better understand interactions between fuel and cladding in research reactor fuels, diffusion couples between γ-phase U-7 wt% Mo and U-10 wt% Mo alloy fuels and a Si-bearing, Al alloy were fabricated using a friction stir welding technique. The advantage of such a fabrication technique is that it can potentially reduce the amount of aluminum-oxide that might be present at the diffusion couple interface. The presence of oxides at the interface can affect the interdiffusion process. These couples were annealed and characterized using a scanning electron microscope equipped with energy-dispersive and wavelength-dispersive spectrometers. Images were taken of the developed diffusion structures; x-ray maps were generated to identify partitioning behavior of the various components; and, point-to-point analysis was employed to generate composition profiles and to determine phase compositions. To try and determine how the presence of Si in an Al alloy affects the interdiffusion behavior of fuel and cladding components in research reactor nuclear fuels, the results from this study were compared to those from earlier diffusion studies using U-Mo alloys and Al. The formed diffusion zones in some samples annealed for 30 minutes are comprised of Si-rich aluminide phases that appear to be (U,Mo)0.9(Al,Si)4 and (U,Mo)(Si,Al)2, based on composition. The diffusion rates observed and the types of phases that form can be correlated to the stability of the γ-U phase, which is a metastable phase. For a sample annealed for a much longer time, large diffusion structures formed and no Si-rich phases were observed.

Download Full-text

Flow analysis of materials in friction stir welding

Journal of the Mechanical Behavior of Materials ◽

10.1515/jmbm-2018-0020 ◽

2018 ◽

Vol 27 (3-4) ◽

Author(s):

C.B. Jagadeesha

Keyword(s):

Friction Stir Welding ◽

Flow Behavior ◽

Flow Analysis ◽

Leading Edge ◽

Dissimilar Welding ◽

Al Alloy ◽

Layer By Layer ◽

Edge Region ◽

Material Transfer ◽

Friction Stir

AbstractThe aim of this study was to analyze the flow behavior of materials in friction stir welding (FSW) of magnesium (Mg) alloy to aluminum (Al) alloy materials at a low rotational speed of 300 rpm and at a low welding speed of 50 mm/min. It was observed that during the dissimilar welding at 300 rpm, some of the material of the advancing side (AS) rotated almost 360° and transferred to the position just behind the previous position, i.e. initial AS position and some of the material of leading edge region transferred to the trailing edge region and such a change continued. Material transfer takes place layer by layer from front to back portions of the FSW tool; a thin layer of material adhered to the tool in the front portion for every half rotation and transferred to the back portion of the tool and this repeated in subsequent rotations. Wrinkle formation began at the front side of the forward moving tool and as the material transferred to backside they became an onion ring pattern, and this was inevitable because the formation of onion rings instantly in the backside region of the tool was clearly impossible.

Download Full-text

Wear Inducing Phase Transformation of Plasma Transfer Arc Coated Tools during Friction Stir Welding with Al Alloy

Journal of Engineering ◽

10.1155/2019/6413608 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Kuan-Jen Chen ◽

Fei-Yi Hung ◽

Truan-Sheng Lui ◽

Yong-Ren Shih

Keyword(s):

Wear Resistance ◽

Phase Transformation ◽

Friction Stir Welding ◽

High Speed ◽

Phase Transfer ◽

Welding Process ◽

High Speed Steel ◽

Al Alloy ◽

Transfer Layer ◽

Friction Stir

The friction stir welding process (friction stir welding/processing, FSW/FSP) has wear problems related to stirring tools. In this study, the plasma transfer arc (PTA) method was used with stellite 1 powders (Co-based) to coat on the head of a SKD61 stirring tool (SKD61-ST1) in order to investigate the wear performance and phase transformation of SKD61-ST1 after FSW. Under the same experimental parameters, the wear data were compared with the high-speed steel SKH51 (tempering material SKH51-T and annealed material SKH51-A) and tungsten-carbide cobalt (TCC). Results showed the PTA coating was a γ-Co solidification matrix with M7C3 and M23C6 carbides. After FSW, the wear resistance of SKD61-ST1 was better than that of SKH51-A and SKH51-T and lower than that of TCC. The SKD61-ST1, SKH51-A, and SKH51-T stirring tools exhibited sliding wear after FSP, where the pin and shoulder of the stirring tool formed a phase transfer layer on the surface, and the peeling of the phase transfer layer caused wear weight loss. The main phase of the phase transfer layer of the SKD61-ST1 tool was Al9Co2. The affinity and adhesion energy of the Co-Al phase was lower than that of Fe-Al phase, and the phase transfer layer of the SKD61-ST1 tool was thinner and had lower coverage, thereby increasing the wear resistance of the SKD61-ST1 stirring tools during FSW.

Download Full-text