Experimental Estimation of Strain Rate during FSW of Al-Alloy Using Plane-Strain Compression

2008 ◽  
Vol 580-582 ◽  
pp. 299-302 ◽  
Author(s):  
Kunitaka Masaki ◽  
Yutaka S. Sato ◽  
Masakatsu Maeda ◽  
Hiroyuki Kokawa
Keyword(s):  
Strain Rate ◽  
Plane Strain ◽  
Travel Speed ◽  
Plane Strain Compression ◽  
Stir Zone ◽  
Grain Structure ◽  
Al Alloy ◽  
Strain Rates ◽  
Friction Stir ◽  
Grain Structures

Friction stir welding (FSW) makes the stir zone with fine recrystallized grain structure. The recrystallized grains would be formed through dynamic recrystallization at high temperatures and high strain-rate. The present study experimentally simulated the dynamically recrystallized microstructure of a friction stir welded Al alloy 1050 produced at 600 rpm rotation and 100 mm/min travel speed, using combination of the plane-strain compression at various strain rates and the subsequent cooling along the cooling cycle of FSW. The equiaxed grain structures similar to the microstructure of the stir zone were produced at strain rates between 0.1 and 32 s-1; the grain size decreased with increasing strain rate. Strain rate during the FSW could be estimated to be about 1.8 s-1. The present study suggests that plane-strain compression test can simulate the recrystallized grain structure of the friction stir welds.

An Investigation of the Dynamic Recrystallisation Behaviour of Magnesium AZ31 Alloy at 450°C Using Plane Strain Compression Testing as a Tool

2012 ◽  
Vol 715-716 ◽  
pp. 164-169
Author(s):  
Bradley P. Wynne ◽  
R. Bhattacharya ◽  
Bruce Davis ◽  
W.M. Rainforth
Keyword(s):  
Strain Rate ◽  
Plane Strain ◽  
Testing Machine ◽  
Az31 Alloy ◽  
Plane Strain Compression ◽  
Strain Rates ◽  
Basal Texture ◽  
Magnesium Az31 ◽  
Dynamic Recrystallisation ◽  
Double Hit

The dynamic recrystallisation (DRX) behaviour of magnesium AZ31 is investigated using a plane strain compression (PSC) testing machine at 450°C. The variables included strain rate, double hit including intermittent anneal and double hits with different strain rate at each hit. The alloy shows higher peak stress and strain with increasing strain rates. Predominant basal texture with different intensities are observed at different strain rates. The annealing treatment between double tests leads to strong basal texture. Reversal of strain rate during double hit results in similar flow curves. This shows that in AZ31 alloy, DRX mechanism is independent of the initial microstructure and only depends on the test condition viz. temperature, strain rate and total equivalent strain.

An Investigation of Microstructure Inhomogeneity in Waspaloy Subjected to Plane Strain Compression Testing

2007 ◽  
Vol 558-559 ◽  
pp. 589-594 ◽  
Author(s):  
M.J. Thomas ◽  
Bradley P. Wynne ◽  
Eric J. Palmiere ◽  
Ken P. Mingard ◽  
Bryan Roebuck
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Plane Strain ◽  
High Strain ◽  
Plane Strain Compression ◽  
Strain Rates ◽  
Nickel Based Superalloy ◽  
Nominal Strain ◽  
Plane Strain Compression Test ◽  
Low Strain Rate

An assessment of the inhomogeneity of microstructure generated within plane strain compression test specimens has been performed using the nickel based superalloy, Waspaloy. Two variables were investigated: the effect of strain rate and the effect of friction at the tool/specimen interface. Tests were performed at 1040°C at nominal strain rates of 0.01 and 1 s-1 with and without a glass based lubricant. At the low strain rate the microstructure was relatively homogeneous regardless of the friction conditions. At the high strain rate there was significant microstructure variation from surface to mid plane which was further exaggerated by increased friction. Quantification of the inhomogeneity, however, is non-trivial in this alloy due to the complicated recrystallisation behaviour it exhibits and difficulty in differentiating between recrystallised and non-recrystallised grains.

Hot Workability of Ultrafine-Grained Aluminum Alloy Produced by Severe Plastic Deformation of Al6063 Powder and Consolidation

2010 ◽  
Vol 667-669 ◽  
pp. 979-984 ◽  
Author(s):  
Hamed Asgharzadeh ◽  
Abdolreza Simchi ◽  
Hyoung Seop Kim
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Grain Structure ◽  
Al Alloy ◽  
Strain Rates ◽  
Hot Workability ◽  
Ultrafine Grained

Al6063 powder was subjected to severe plastic deformation via high-energy mechanical milling to prepare ultrafine-grained (UFG) aluminium alloy. Uniaxial compression test at various temperatures between 300 and 450 °C and strain rates between 0.01 and 1 s-1 was carried out to evaluate hot workability of the material. Microstructural studies were performed by EBSD and TEM. The average activation energy and strain rate sensitivity of the hot deformation process were determined to be 280 kJ mol-1 and 0.05, respectively. The deformation temperature and applied strain rate significantly affected the grain structure of UFG Al alloy. A finer grain structure was obtained at lower temperatures and higher strain rates. The formation of highly misoriented and equiaxed grains also revealed that dynamic recrystallization occurred upon hot deformation. Furthermore, elongated grains with high dislocation density were observed that disclosed partial dynamic recrystallization of the aluminum matrix.

scholarly journals Bobbin Tool Friction Stir Welding of Aluminum Thick Lap Joints: Effect of Process Parameters on Temperature Distribution and Joints’ Properties

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4585
Author(s):  
Mohamed M. Z. Ahmed ◽  
Mohamed I. A. Habba ◽  
Mohamed M. El-Sayed Seleman ◽  
Khalil Hajlaoui ◽  
Sabbah Ataya ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Welding Speed ◽  
Travel Speed ◽  
Lap Joints ◽  
Stir Zone ◽  
Maximum Temperature ◽  
Al Alloy ◽  
Friction Stir ◽  
Pin Geometry ◽  
Zone Temperature

Bobbin tool friction stir welding (BT-FSW) is characterized by a fully penetrated pin and double-sided shoulder that promote symmetrical solid-state joints. However, control of the processing parameters to obtain defect-free thick lap joints is still difficult and needs more effort. In this study, the BT-FSW process was used to produce 10 mm AA1050-H14 similar lap joints. A newly designed bobbin tool (BT) with three different pin geometries (cylindrical, square, and triangular) and concave shoulders profile was designed, manufactured, and applied to produce the Al alloy lap joints. The experiments were carried out at a constant tool rotation speed of 600 rpm and a wide range of various welding travel speeds of 200, 400, 600, 800, and 1000 mm/min. The generated temperature during the BT-FSW process was recorded and analyzed at the joints’ center line, and at both advancing and retreating sides. Visual inspection, macrostructures, hardness, and tensile properties were investigated. The fracture surfaces after tensile testing were also examined. The results showed that the pin geometry and travel speed are considered the most important controlling parameters in BT-FSW thick lap joints. The square (Sq) pin geometry gives the highest BT-FSW stir zone temperature compared to the other two pins, cylindrical (Cy) and triangular (Tr), whereas the Tr pin gives the lowest stir zone temperature at all applied travel speeds from 200 to 1000 mm/min. Furthermore, the temperature along the lap joints decreased with increasing the welding speed, and the maximum temperature of 380 °C was obtained at the lowest travel speed of 200 mm/min with applying Sq pin geometry. The temperature at the advancing side (AS) was higher than that at the retreating side (RS) by around 20 °C. Defect-free welds were produced using a bobbin tool with Cy and Sq pin geometries at all the travel welding speeds investigated. BT-FSW at a travel speed of 200 mm/min leads to the highest tensile shear properties, in the case of using the Sq pin. The hardness profiles showed a significant effect for both the tool pin geometry and the welding speed, whereas the width of the softened region is reduced dramatically with increasing the welding speed and using the triangular pin.

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

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.

Where Does the Lithium Go? - A Study of the Precipitates in the Stir Zone of a Friction Stir Weld in a Li-containing 2xxx Series Al Alloy

2010 ◽  
pp. NA-NA ◽  
Author(s):  
Jiancun Rao ◽  
Eric J. Payton ◽  
Christoph Somsen ◽  
Klaus Neuking ◽  
Gunther Eggeler ◽  
...  
Keyword(s):  
Stir Zone ◽  
Friction Stir Weld ◽  
Al Alloy ◽  
Friction Stir

Texture Formation Behaviour during High-Temperature Plane Strain Compression Deformation in AZ91 Magnesium Alloy

2018 ◽  
Vol 941 ◽  
pp. 1198-1202
Author(s):  
Dong Keun Han ◽  
Min Soo Park ◽  
Han Sang Kwon ◽  
Kwon Hoo Kim
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Plane Strain ◽  
Texture Evolution ◽  
Plane Strain Compression ◽  
Deformation Condition ◽  
Rolled Plate ◽  
Pole Density ◽  
Texture Formation ◽  
Compression Tests

In previous study, it was investigated texture formation behaviour of high-temperature plane strain compression test at 723K, under a strain rate of 5.0. It was found that the main texture component and it was sharpness vary depending on deformation conditions. To clarify the characteristic of texture formation behaviour, it is necessary to investigate at various deformation condition. Therefore, in this study, is investigating the influence or texture formation behaviour and strain, strain rate at 673K. Three kinds of specimens with different initial textures were machined out from a rolled plate having a <0001> texture. The plane strain compression tests were conducted at a temperature 673K, and a strain rate of 5.0, with strain between-0.4 to-1.0. After compression tests, the specimens were immediately quenched in oil. The texture evolution was conducted by the Schulz reflection method using Cu Kα radiation and EBSD. Before the deformation, {0001} of specimen A was accumulated in the center of pole figure. The {0001} of specimen B was accumulated at the RD direction. The {0001} of specimen C was accumulated TD direction. As a result, work softening is observed in all the cases at the true stress – true strain curve for three types of specimens. After deformation, the maximum pole density of increases with increasing strain. In this study, it was found that the stable orientation was (0001)<100> and (0001)<110> during deformation.

scholarly journals Texture Evolution in AA6082-T6 BFSW Welds: Optical Microscopy and EBSD Characterisation

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3215 ◽  
Author(s):  
Abbas Tamadon ◽  
Dirk J. Pons ◽  
Don Clucas ◽  
Kamil Sued
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Optical Microscopy ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Grain Structure ◽  
Friction Stir ◽  
Fine Grain ◽  
Grain Structures ◽  
Dynamic Recrystallisation

One of the difficulties with bobbin friction stir welding (BFSW) has been the visualisation of microstructure, particularly grain boundaries, and this is especially problematic for materials with fine grain structure, such as AA6082-T6 aluminium as here. Welds of this material were examined using optical microscopy (OM) and electron backscatter diffraction (EBSD). Results show that the grain structures that form depend on a complex set of factors. The motion of the pin and shoulder features transports material around the weld, which induces shear. The shear deformation around the pin is non-uniform with a thermal and strain gradient across the weld, and hence the dynamic recrystallisation (DRX) processes are also variable, giving a range of observed polycrystalline and grain boundary structures. Partial DRX was observed at both hourglass boundaries, and full DRX at mid-stirring zone. The grain boundary mapping showed the formation of low-angle grain boundaries (LAGBs) at regions of high shear as a consequence of thermomechanical nature of the process.

scholarly journals Microstructure and Corrosion Behavior of Friction Stir-Welded 6061 Al/AZ31 Mg Joints with a Zr Interlayer

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1115 ◽  
Author(s):  
Yang Zheng ◽  
Xiaomeng Pan ◽  
Yinglei Ma ◽  
Shuming Liu ◽  
Libin Zang ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Stir Zone ◽  
Thermal Barrier ◽  
Al Alloy ◽  
X Ray ◽  
Friction Stir ◽  
Base Materials ◽  
Dissimilar Alloys ◽  
Scanning Electron

Friction stir welding (FSW) with a Zr interlayer was employed to join dissimilar alloys of 6061 Al and AZ31 Mg. The microstructures of Al/Mg and Al/Zr/Mg joints were investigated by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometer (EDS). The results showed that the central part of the Zr interlayer was smashed and intermixed with the base materials in the stir zone, whereas the undamaged part remained stable at the Al/Mg interface. The formation of Al–Mg intermetallic compounds (IMCs) was suppressed by the Zr interlayer due to its synergetic effects of chemical modification and thermal barrier. The electrochemical measurements revealed a differentiated corrosion behavior for each joint, where the corrosion rate of representative regions increased in the order of Al alloy < Mg alloy < heat-affected zone < stir zone. The immersion tests indicated an enhancement in corrosion resistance for the Al/Zr/Mg joint compared with the Al/Mg joint, which is owing to the mitigated galvanic corrosion between the base materials by the Zr interlayer.

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