scholarly journals A Study of the Metallurgical and Mechanical Properties of Friction-Stir-Processed Cu

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 656
Author(s):  
Michael Regev ◽  
Stefano Spigarelli
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Parent Material ◽  
Stir Zone ◽  
New Approach ◽  
Friction Stir ◽  
Fine Grain ◽  
Plastic Deformation Process ◽  
Uniform Cross Section ◽  
Pure Cu

Friction stir processing (FSP), a severe plastic deformation process, was applied on pure Cu to obtain a stir zone with a very fine grain size. Yet, when FSP is used, the stir zone is as wide as the diameter of the shoulder at the upper surface of the weld and markedly narrower near its opposite surface. This property, as well as the differences between the advancing side and the retreating side, makes it impossible to obtain a uniform cross-section as far as the microstructure and mechanical properties are concerned. For these reasons, a new approach is proposed in which the material was processed on both sides, thus yielding a wider, rectangular and more homogenous stir zone from which all the specimens were machined out. Processing the material from both sides eliminated any microstructural difference between the upper and the lower side, at least within the gauge length’s cross-section of the creep specimens. Although grain refinement was detected, the mechanical properties of the friction-stir-processed (FSP’ed) material are inferior relative to those of the parent material. The TEM study reported in the current paper revealed the existence of nanosized grains in the FSP’ed material due to dynamic recrystallization (DRX) occurring during the processing stage. Because both X-ray inspection and fractography showed that the FSP’ed material was free of defects, the material may not comply with the Hall–Petch relation due to lower dislocation density caused by XRD occurring during FSP. The inverse Hall–Petch effect may also be considered as an assistive mechanism in mechanical property deterioration.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

scholarly journals The Effect of Vibration during Friction Stir Welding on Corrosion Behavior, Mechanical Properties, and Machining Characteristics of Stir Zone

Metals ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. 421 ◽  
Author(s):  
Sajad Fouladi ◽  
Amir Ghasemi ◽  
Mahmoud Abbasi ◽  
Morteza Abedini ◽  
Amir Khorasani ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Corrosion Behavior ◽  
Stir Zone ◽  
Friction Stir ◽  
Machining Characteristics

The Use of Bobbin Tools for Friction Stir Welding of Aluminium Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1179-1184 ◽  
Author(s):  
Philip L. Threadgill ◽  
M.M.Z. Ahmed ◽  
Jonathan P. Martin ◽  
Jonathan G. Perrett ◽  
Bradley P. Wynne
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Friction Stir Welding ◽  
Cross Section ◽  
Axial Force ◽  
Aluminium Alloys ◽  
Processing Parameters ◽  
Machine Design ◽  
Friction Stir ◽  
Triangular Zone

The use of a double sided friction stir welding tool (known as a bobbin tool) has the advantage of giving a processed zone in the workpiece which is more or less rectangular in cross section, as opposed the triangular zone which is more typically found when conventional friction stir welding tool designs are used. In addition, the net axial force on the workpiece is almost zero, which has significant beneficial implications in machine design and cost. However, the response of these tools in generating fine microstructures in the nugget area has not been established. The paper presents detailed metallographic analyses of microstructures produced in 25mm AA6082-T6 aluminium wrought alloy, and examines grain size, texture and mechanical properties as a function of processing parameters and tool design, and offers comparison with data from welds made with conventional tools.

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.

scholarly journals Microstructure and Mechanical Properties of Friction Stir Welded Joints Between Commercially Pure Copper and Al 6351 Alloy

2017 ◽  
Vol 62 (3) ◽  
pp. 1819-1825
Author(s):  
V.C. Sinha ◽  
S. Kundu ◽  
S. Chatterjee
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Rotational Speed ◽  
Pure Copper ◽  
Stir Zone ◽  
Tool Rotational Speed ◽  
Friction Stir ◽  
Commercially Pure ◽  
Microstructure And Mechanical Properties ◽  
Commercially Pure Copper

AbstractIn the present study, the effect of tool rotational speed on microstructure and mechanical properties of friction stir welded joints between commercially pure copper and 6351 Al alloy was carried out in the range of tool rotational speeds of 300-900 rpm in steps of 150 rpm at 30 mm/minutes travel speed. Up to 450 rpm, the interface of the joints is free from intermetallics and Al4Cu9intermetallic has been observed at the stir zone. However, Al4Cu9intermetallic was observed both at the interface and the stir zone at 600 rpm. At 750 and 900 rpm tool rotational speed, the layers of AlCu, Al2Cu3and Al4Cu9intermetallics were observed at the interface and only Al4Cu9intermetallics has been observed in the stir zone. The maximum ultimate tensile strength of ~207 MPa and yield strength of ~168 MPa along with ~6.2% elongation at fracture of the joint have been obtained when processed at 450 rpm tool rotational speed.

Mechanical Properties and Fracture Toughness of Aluminum Vessels by Friction Stir Welding

2004 ◽  
Author(s):  
Masahito Mochizuki ◽  
Masao Toyoda ◽  
Masayuki Inuzuka ◽  
Hidehito Nishida
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Crack Initiation ◽  
Base Metal ◽  
Welded Joint ◽  
Stir Zone ◽  
Crack Initiation And Propagation ◽  
Friction Stir ◽  
Fine Grained ◽  
Initiation And Propagation

Mechanical properties and fracture toughness in friction stir welded joint of vessels of structural aluminum alloy type A5083-O are investigated. Welded joint from 25 mm-thick plate is fabricated by one-side one-pass friction stir. Charpy impact energy and critical crack-tip opening displacement (CTOD) in friction stir weld are much higher than those of base metal or heat-affected zone, whereas mechanical properties such as stress-strain curve and Vickers hardness do not have a conspicuous difference. Effects of microstructure on crack initiation and propagation are studied in order to clarify the difference of fracture toughness between stir zone and base metal. Both tensile test and bending test show that the fine-grained microstructure in stir zone induces to increase ductile crack initiation and propagation resistance by analyzing fracture resistance curves and diameter of dimples in fracture surface. It is found that high fracture toughness value in stir zone is affected fine-grained microstructure by friction stirring.

Effect of Enhanced Cooling on the Microstructure and Mechanical Properties of Friction Stir Spot-Welded AZ31 Magnesium Alloy

2016 ◽  
Vol 850 ◽  
pp. 784-789
Author(s):  
Song Lin Chen ◽  
Da Tong Zhang
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Cooling Water ◽  
Stir Zone ◽  
Az31 Magnesium Alloy ◽  
Air Cooling ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Spot Welded

AZ31 magnesium alloy was friction stir spot welded in air and cooling in water. The effect of the enhanced cooling rate on the microstructure and mechanical properties of the joint was analyzed. The results showed that flowing water had obvious cooling effect instantaneously, which significantly restrained the growth of dynamic recrystallized grains. The average grain size in stir zone was 1.3μm in cooling water condition, which is far smaller than that of the joint prepared in air cooling condition. Under the condition of enhanced cooling, the microhardness in stir zone significantly increased, the ultimate tensile load (~ 3.99kN) increased by 15.7%, and the tensile deformation value (~ 3.65 mm) increased by 62.2%. Dimples in SEM fracture morphologies indicated the better plastic deformation capacity of joints prepared by cooling water, which failed through a mixture mode of ductile and brittle fracture.

Microstructures and Properties of Biological Mg-Zn-Y-Nd Alloy by Friction Stir Processing

2013 ◽  
Vol 745-746 ◽  
pp. 33-38 ◽  
Author(s):  
Shi Jie Zhu ◽  
Li Guo Wang ◽  
Jin Jin ◽  
Jing Wang ◽  
Yu Feng Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Processing ◽  
Cast Alloy ◽  
Corrosion Current ◽  
Stir Zone ◽  
Grain Structure ◽  
Second Phase ◽  
Uniform Corrosion ◽  
Corrosion Properties ◽  
Friction Stir

In order to improve the mechanical properties and processing performance of the Mg alloys, and to prevent magnesium alloy from non-uniform corrosion and too fast degradation in the degradation process, the biological medical Mg-Zn-Y-Nd alloy was modified by the friction stir processing (FSP) technique in this paper. The microstructural evolution and phase constitute of the stir zone of Mg-Zn-Y-Nd alloy were investigated, the microhardness and the corrosion properties of the alloy after FSP process was studied. The results showed that the FSP parameters had significant influence on the stir zone and thermo-mechanically affected zone. The stir zone experienced severe plastic deformation and complete dynamic recrystallization after FSP. The stir zone consists of fine equiaxed recystallized grains, and thermo-mechanically affected zone (TMAZ) has deformed grain structure. The second phase distributed along grain boundaries in as-cast state was broken during the FSP and transformed into fine, uniform and dispersed particles in the grains. After FSP, the size of grains was reduced from 50μm (as-cast alloy) to 1-2μm. However, the second phase constitution didnt change. The alloy obtained good comprehensive mechanical properties after FSP. The microhardness of alloy after FSP increased from 39HV (as-cast alloy) to 64HV(FSPed alloy). The results of electrochemical tests in simulated body fluid showed that the corrosion potential of FSP alloy increased and corrosion current density decreased, which confirmed the uniform corrosion of FSPed alloy.

Investigation of Microstructure and Mechanical Properties of Friction Stir Lap Jointed Ni Base Superalloy

2012 ◽  
Vol 724 ◽  
pp. 481-485
Author(s):  
Kuk Hyun Song ◽  
Kazuhiro Nakata
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Friction Stir Welding ◽  
Base Material ◽  
Lap Joints ◽  
Stir Zone ◽  
Inconel 600 ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

This study evaluated the microstructure and mechanical properties of friction stir welded lap joints. Inconel 600 and SS 400 as experimental materials were selected, and friction stir welding was carried out at tool rotation speed of 200 rpm and welding speed of 100 mm/min. Applying the friction stir welding was notably effective to reduce the grain size of the stir zone, as a result, the average grain size of Inconel 600 was reduced from 20 μm in the base material to 8.5 μm in the stir zone. Joint interface between Inconel 600 and SS 400 showed a sound weld without voids and cracks. Also, the hook, along the Inconel 600 alloy from SS 400, was formed at advancing side, which directly affected an increase in peel strength. In this study, we systematically discussed the evolution on microstructure and mechanical properties of friction stir lap jointed Inconel 600 and SS 400.

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