scholarly journals Nanoindentation Hardness Distribution and Strain Field and Fracture Evolution in Dissimilar Friction Stir-Welded AA 6061-AA 5A06 Aluminum Alloy Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Guangjian Peng ◽  
Yi Ma ◽  
Jiangjiang Hu ◽  
Weifeng Jiang ◽  
Yong Huan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Strain Field ◽  
Optical Microscope ◽  
Image Correlation ◽  
Grain Structure ◽  
Structure Evolution ◽  
Hardness Distribution ◽  
Slant Angle ◽  
Friction Stir

Aluminum alloy AA 6061-T651 and 5A06-H112 rolled plates were successfully welded by friction stir welding (FSW) at three rotation speeds of 600, 900, and 1200 rpm with two transverse speeds of 100 and 150 mm/min. Mechanical properties and strain field evolution of FSW AA 6061-AA 5A06 were characterized by the uniaxial tension and digital image correlation (DIC) tests. Furthermore, the hardness distribution map of whole cross section was obtained via the nanoindentation method with 700 indents. Both DIC and nanoindentation results reveal that the heat-affected zone (HAZ) of AA 6061 alloy is the softest area in the weldment, and the fracture happens in this region. The microstructure evolution characterized by electron-backscatter diffraction (EBSD) indicates that the continuous dynamic recrystallization is the primary grain structure evolution in the stirring zone, and the grain refinement helps improve the mechanical properties. Analyses of the micro- and macrofeatures of the fracture surfaces via scanning electron microscopy (SEM) and optical microscope suggest that the increasing of heat input could enlarge the size of HAZ and reduce the slant angle of HAZ and thus lead the fracture angle to decrease and cause the dimples change from inclined ones to normal ones.

Study on the Microstructure and Mechanical Properties of Welding Joints of 7A05 Aluminum Alloy by FSW

2014 ◽  
Vol 496-500 ◽  
pp. 110-113
Author(s):  
Dong Gao Chen ◽  
Jin He Liu ◽  
Zhi Hua Ma ◽  
Wu Lin Yang
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Welded Joint ◽  
Optical Microscope ◽  
Nugget Zone ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Welding Joints

The7A05 aluminum alloy of the 10mm thickness was welded by the friction stir welding. The microstructure and mechanical Properties of the welded joint was researched by the optical microscope, etc. The results showed: the microstructure of the weld nugget zone and the thermal mechanically affected zone were refined as the welding speed increasing when the rotate speed is constant. As the welding speed increasing the strength of extension of the welded joint is increasing at first and then stable basically. but the yield strength had no obvious change.

scholarly journals Microstructure Evolution and Mechanical Property Characterization of 6063 Aluminum Alloy Tubes Processed with Friction Stir Back Extrusion

JOM ◽  
2019 ◽  
Vol 71 (12) ◽  
pp. 4436-4444
Author(s):  
Suhong Zhang ◽  
Alan Frederick ◽  
Yiyu Wang ◽  
Mike Eller ◽  
Paul McGinn ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Microstructure Evolution ◽  
Electron Backscatter Diffraction ◽  
Deformation Gradient ◽  
Optical Microscope ◽  
Grain Structure ◽  
Frictional Heat ◽  
Friction Stir ◽  
Metal Extrusion ◽  
Backscatter Diffraction

Abstract Friction stir back extrusion (FSBE) is a technique for lightweight metal extrusion. The frictional heat and severe plastic deformation of the process generate an equiaxed refined grain structure because of dynamic recrystallization. Previous studies proved that the fabrication of tube and wire structures is feasible. In this work, hollow cylindrical billets of 6063-T6 aluminum alloy were used as starting material. A relatively low extrusion ratio allows for a temperature and deformation gradient through the tube wall thickness to elucidate the effect of heat and temperature on the microstructure evolution during FSBE. The force and temperature were recorded during the processes. The microstructures of the extruded tubes were characterized using an optical microscope, energy-dispersive x-ray spectroscopy, electron backscatter diffraction, and hardness testing. The process reduced the grain size from 58.2 μm to 20.6 μm at the inner wall. The microhardness of the alloy was reduced from 100 to 60–75 HV because of the process thermal cycle.

Wear and Mechanical Properties of Aluminum Alloy Based Hybrid Composites [(SiC+Gr) and (SiC+Al2O3)] Fabricated by Friction Stir Processing

2013 ◽  
Author(s):  
A. Kumar ◽  
A. Devaraju ◽  
B. Kotiveerachari
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Rotational Speed ◽  
Solid Lubricant ◽  
Hybrid Composites ◽  
Optical Microscope ◽  
High Wear Resistance ◽  
Nugget Zone ◽  
Friction Stir

In this investigation, the influence of tool rotational speed on wear and mechanical properties of Aluminum alloy based surface hybrid composites fabricated via Friction stir processing (FSP) was studied. The fabricated surface hybrid composites have been examined by optical microscope for dispersion of reinforcement particles. Microstructures of all the surface hybrid composites revealed that the reinforcement particles (SiC, Gr and Al2O3) are uniformly dispersed in the nugget zone. It is observed that the microhardness is decreased with increasing the rotational speed and exhibited higher microhardness value in Al-SiC/Al2O3 surface hybrid composite at a rotational speed of 900 rpm, due to presence and pining effect of hard SiC and Al2O3 particles. It is also observed that high wear resistance exhibited in the Al-SiC/Gr surface hybrid composites at a rotational speed of 900 rpm due to presence of SiC and Gr acted as load bearing elements and solid lubricant respectively. The observed wear and mechanical properties have been correlated with microstructures and worn morphology.

On the Manufacture of Lightweight Alloy Tubes via Friction Stir Back Extrusion: Process Evaluation and Material Performance

2014 ◽  
Author(s):  
Justin L. Milner ◽  
Fadi Abu-Farha
Keyword(s):  
Mechanical Properties ◽  
Extrusion Process ◽  
General Concept ◽  
Electron Back Scatter Diffraction ◽  
Image Correlation ◽  
Grain Structure ◽  
Friction Stir ◽  
Power Measurements ◽  
Tubular Specimens ◽  
Comprehensive Study

A new manufacturing approach in which the friction stirring phenomenon is used as a vehicle for facilitating the deformation of bulk lightweight materials into manufactured components has been recently introduced under the general concept of “bulk friction stir forming”. In a preliminary work, the concept was applied to the back extrusion process, in what was referred to as “friction stir back extrusion” or FSBE; it was shown that the concept is practically valid and FSBE is capable of producing lightweight tubular specimens. Nevertheless, the FSBE process was claimed to have several merits over conventional processes, mainly: (i) unique process capabilities and energy efficiency (ii) significant grain refinement, and thus (iii) favorable mechanical properties in the formed tubes. None of these claims were adequately addressed nor quantified in earlier work. Therefore, this work presents a comprehensive study that aims to reveal the true merits of FSBE, validate the claims, and quantify its effects on the microstructure and mechanical properties of the deformed material. The outcomes of the study are presented in three major parts, each addressing one of the abovementioned claims. Force, torque and power measurements during FSBE experiments are used to address the first claim. Detailed optical microscopy and electron back scatter diffraction work is carried out in the second part to quantify the changes to the grain structure and texture of the material. Finally, the third part presents detailed mechanical characterization using digital image correlation to quantify the effects of FSBE on the performance of the produced tubes.

scholarly journals Grain structure evolution during friction-stir welding of 6061-T6 aluminum alloy

2021 ◽  
Vol 1014 (1) ◽  
pp. 012015
Author(s):  
A Kalinenko ◽  
I Vysotskiy ◽  
S Malopheyev ◽  
S Mironov ◽  
R Kaibyshev
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Grain Structure ◽  
Structure Evolution ◽  
Friction Stir

Microstructure and Mechanical Properties of Friction Stir Welded Al-Zn-Mg-Cu Alloy

2014 ◽  
Vol 628 ◽  
pp. 7-11
Author(s):  
Sheng Dan Liu ◽  
Yun Dai ◽  
Yu Long Wu ◽  
Bin Chen ◽  
Xin Ming Zhang
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Base Material ◽  
Optical Microscope ◽  
Alloy Sheet ◽  
Grain Structure ◽  
Hardness Profile ◽  
Friction Stir ◽  
Cu Alloy ◽  
Microstructure And Mechanical Properties

The microstructure and mechanical properties of friction stir welded Al-Zn-Mg-Cu alloy sheet were investigated by means of hardness and tensile tests, optical microscope and scanning electron microscope. The hardness profile of the weld exhibits a W shape with the lowest value in the thermo-mechanically affected zone on the advancing side. The tensile strength and elongation of the weld are about 71% and 72% that of the base material. In the nugget zone, there are a number of fine recrystallized grains and dispersed precipitates at grain boundaries. In the thermo-mechanically affected zone, the grain size is not uniform and there are a number of precipitates at grain boundaries. In the heat affected zone, the grain structure is similar to the base material.

scholarly journals Effect of PWHT on the Microstructure and Mechanical Properties of Friction Stir Welded DP780 Steel

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1097
Author(s):  
Umer Masood Chaudry ◽  
Seung-Chang Han ◽  
Fathia Alkelae ◽  
Tea-Sung Jun
Keyword(s):  
Mechanical Properties ◽  
Annealing Temperature ◽  
Tensile Elongation ◽  
Image Correlation ◽  
Frictional Heat ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Dp780 Steel

In the present study, the effect of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of friction stir welded (FSW) DP780 steel sheets was investigated. FSW was carried out at a constant tool rotation speed of 400 rpm and different welding speeds (200 mm/min and 400 min/min). A defect free weld was witnessed for both of the welding conditions. The mutual effect of severe plastic deformation and frictional heat generation by pin rotation during the FSW process resulted in grain refinement due to dynamic recrystallization in the stir zone (SZ) and thermo-mechanically affected zone (TMAZ). Lower tensile elongation and higher yield and ultimate tensile strengths were recorded for welded-samples as compared to the base material (BM) DP780 steel. The joints were subsequently annealed at various temperatures at 450–650 °C for 1 h. At higher annealing temperature, the work hardening rate of joints gradually decreased and subsequently failed in the softened heat-affected zone (HAZ) during the uniaxial tensile test. Reduction in yield strength and tensile strength was found in all PWHT conditions, though improvement in elongation was achieved by annealing at 550 °C. The digital image correlation analysis showed that an inhomogeneous strain distribution occurred in the FSWed samples, and the strain was particularly highly localized in the advancing side of interface zone. The nanoindentation measurements covering the FSWed joint were consistent with an increase of the annealing temperature. The various grains size in the BM, TMAZ, and SZ is the main factor monitoring the hardness distribution in these zones and the observed discrepancies in mechanical properties.

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