Mechanical Properties Of Friction Stir Research Articles

Effect of Process Parameters and Tool Pin Profiles on Microstructural Evolution and Mechanical Properties of Friction Stir Welded AA5052

Effect of Process Parameters and Tool Pin Profiles on Microstructural Evolution and Mechanical Properties of Friction Stir Welded AA5052

Influence of post-weld rolling and artificial aging on microstructure and mechanical properties of friction stir welded 2195-T4 Al-Li alloy joints

Fiction stir welding (FSW) of a naturally aged (T4) 2195 Al-Li alloy was conducted to study the effect of post-weld artificial aging (AA) and rolling+artificial aging (R+AA) on microstructure and mechanical properties of the FSW joints. Grain features were analyzed by electron back scattered diffraction (EBSD) technology, and precipitates were characterized using transmission electron microscopy (TEM) along [011]Al and [001]Al zone axes. Mechanical properties of the joints were evaluated through micro-hardness and tensile testing. The results indicate that grain development, including grain orientation, grain boundary components and dislocation density, varies within different regions of the As-welded joints due to complicated thermal-mechanical history. The alloying elements mostly exist as Guinier-Preston zones in the base material (BM) with a few formations of δ'/β', and slightly precipitate into T1 in the heat affected zone (HAZ), form σ in the thermal-mechanical affected zone (TMAZ), as well as develop T1 and S' in the nugget zone (NZ) after FSW. The lowest hardness zone (LHZ) exhibits elevated precipitation levels, generating coarse T1 and grain boundary precipitates with evident σ and precipitate free zone. The overall precipitation level of the As-welded joints remains minor, resulting in a slight decrease in hardness at the LHZ. Post-weld AA promotes many T1 formations, enhancing the joint strength and hardness. As a result, the ultimate tensile strength (UTS) of the joints increases from 440 MPa to 506.5 MPa, while the elongation decreases from 13.5% to 3.4%. Furthermore, hardness profiles transform from a low-amplitude wave curve to a high-amplitude W-shaped curve, generating a significant LHZ due to the minimal precipitation of T1. Pre-rolling deformation can enhance dislocation density and low angle grain boundaries (LAGBs), promoting the nucleation of high-density, fine T1 during artificial aging, and especially improves precipitation ability of the LHZ, leading to an elevated hardness increment in the region after AA. Compared to the Joint-AA, both strength and elongation of the Joint-R+AA increase, obtaining 530.5 MPa and 3.9%, respectively.

Effects of Ca contents on microstructures and mechanical properties of friction stir processed Mg alloys

Ca alloying is beneficial for improving the uniform elongation for friction stir processed (FSPed) Mg-4Al-2Sn-xCa (0, 0.5, 1.0 and 1.5 wt.%) (AT42-xCa) alloys. Coarse CaMgSn and Al2Ca particles in as-cast AT42-xCa alloys lead to a sharp decrease in elongation. Friction stir processing (FSP) is effective in improving strength and elongation by refining grain structure along with CaMgSn and Al2Ca particles, and inducing grain orientations with high Schmid factors for basal slip. Consequently, FSPed AT42-0.5Ca alloy exhibits simultaneously enhanced ultimate tensile strength (∼224 MPa) and elongation (∼30.9%). Compared to the Ca-free alloy, 0.5 wt.% Ca alloying increases the heat input and promotes the dislocation recovery, reducing residual dislocations. Nano-sized CaMgSn precipitates in grain interiors inhibit the dynamic recovery of dislocations during tensile, facilitating the work-hardening ability. Besides, high Schmid factors facilitate basal dislocation slips. Therefore, high EL is primarily due to the dislocation-free fine grain (∼2.7 μm), refined CaMgSn particles (micron-sized particles (∼1.3 μm) and nano-sized precipitates (∼55 nm)) and high Schmid factors (∼0.446) for basal slips.

Implications of nanomaterials reinforcement along with sub-zero temperature cooling on microstructure and mechanical properties of friction stir processed Al7075 alloy

Al 7075 surface composites (SCs) successfully fabricated with additive three different nano-scale particles multi-walled carbon nanotubes (MWCNTs), graphene (GNP), and titanium dioxide (TiO2) by friction stir processing (FSP). The consecutive two-pass FSP was executed under a controlled cooling environment at −20 °C with methanol pumped beneath the workpiece in a specially designed fixture. All of the SCs exhibited homogenous dispersion of filler nanoparticles in their microstructures. The grain size of SCs was remarkably reduced from that of the substrate. The enhancement in hardness and strength was ascribed fundamentally to the grain refinement and Zener (pinning) effect expedited by coolant circulation. The effect of second phase matrix on grain evolution and precipitate-intermetallics formed after FSP was characterized by scanning electron microscope (SEM) and XRD pattern. It has been recorded that there is around 95–110% increase in hardness values in SCs. The wear rate is also dropped in SCs owing to enhanced hardness and the formation of lubricating coating in the case of carbonaceous composites.

Effect of corrosion environments on the mechanical properties of friction stir welded aluminum alloy AA3003

The article presents an experimental study on the corrosion resistance of the 3003 Aluminium alloy Friction Stir Welded (FSW) joint in different working environments. Three types of corrosive media at different temperatures were tested to see how they affected the FSW joint mechanical properties. The media were sodium chloride, hydrogen chloride, and ethylene glycol. In parallel with the study of the effect of temperature, static tensile tests were carried out on specimens taken perpendicular to the welding direction. Also, micro-hardness profiles were used to determine the influence of the parameters studied on the various weld zones. Finally, the effect of the most aggressive corrosive medium, temperature, and the inclusion of ethylene glycol on the crack propagation resistance of an FSW joint were studied. Fatigue-propagation tests at constant stress amplitude were carried out to understand what affects the fatigue crack propagation of welded joints after corrosive attack. The results showed that uniform and pitting corrosion were combined to cause FSW joint surface degradation. Corrosion damage does not appear to alter yield strength and ultimate stress values. However, FSW joints show a significant degradation in mechanical properties with increasing temperature and with the aggressiveness of the corrosive medium. The inclusion of ethylene glycol was found to delay the rate of crack propagation during testing, leading to an improvement in the service life of pre-corroded FSW joints.

Ultrasonic Influence on Macrostructure and Mechanical Properties of Friction Stir Welded Joints of Al/Mg Sheets with 2 mm Thickness.

Friction stir welding (FSW) and ultrasonic vibration enhanced FSW (UVeFSW) experiments were conducted by using 6061-T6 Al alloy and AZ31B-H24 Mg alloy sheets of thickness 2 mm. The suitable process parameters windows were obtained for the butt joining of Al/Mg sheets. The effect of ultrasonic vibration on the macrostructure and mechanical properties of the dissimilar joints was studied. The results showed that the width of the weld nugget zone (WNZ) was enlarged to some extent and the hardness distribution in WNZ was more uniform in UVeFSW. In addition, the application of ultrasonic vibration effectively promoted the interpenetration degree of dissimilar materials in the WNZ so that the mechanical interlocking on the bonding interface of dissimilar Al/Mg materials was enhanced. The facture positions were changed from the bonding interface in FSW to the boundary between WNZ and the thermo-mechanical affected zone, and the ductile fracture zone was expanded. The highest ultimate tensile strength was 205 MPa at the process parameters set of 1200 rpm-50 mm/min in UVeFSW in this experiment. The average ultimate tensile strength of FSW/UVeFSW joints was 172.3 MPa and 184.4 MPa, respectively, and the average ultimate tensile strength was increased by 7.02% with the introduction of ultrasonic vibration.

Microstructures and mechanical properties of friction stir welded additively manufactured Scalmalloy®

The development of high-strength advanced additively manufactured (AM) aluminum alloys is driven by the need for weight reduction in complex-shaped structural applications. In this context, heat-treatable aluminum-scandium alloy, known commercially as Scalmalloy®, offers high strength and lightness, also at high temperatures, due to solution strengthening Al3(Sc, Zr) particles. A widespread diffusion of such AM alloy is also related to welding technologies that could preserve its engineered microstructure. This study investigates the microstructural and mechanical properties of butt friction stir welding (FSW) joints of LPBF Scalmalloy® plates under different welding settings. Joint performance was evaluated under quasi-static and cyclic loading conditions. Porosity in Scalmalloy® and welds was assessed using 3D X-ray computed tomography. An aging heat treatment assessed the extent of precipitation hardening in the FSW joints. Results show that metal stirring during FSW notably reduced the intrinsic porosity of Scalmalloy®, decreasing the equivalent pore diameter from about 200 μm to 60 μm in the welded joints. Under quasi-static loading, welded specimens failed at the interface between the thermo-mechanically affected and the stir zones on the advancing side. The aging heat treatment improved the mechanical strength of Scalmalloy® from approximately 400 to 480 MPa, albeit at the expense of ductility (elongation at fracture decreased from 16 to 4%). The higher heat input and stirring developed at a low welding speed reduced lazy S defects but limited the effectiveness of subsequent aging. In fatigue testing, welded joints consistently failed within the aged base material due to the intrinsic porosity of Scalmalloy®.

An investigation of the effect of auxiliary pins on mechanical properties of friction stir welded AA2024-T351

An investigation of the effect of auxiliary pins on mechanical properties of friction stir welded AA2024-T351

Welding Speed and Pin Penetration Interaction in Mechanical Properties of Friction Stir Welded Lap-Joint AA6061/316 Stainless Steel

Welding Speed and Pin Penetration Interaction in Mechanical Properties of Friction Stir Welded Lap-Joint AA6061/316 Stainless Steel

Effect of Tool Rotational Speed on Microstructure and Mechanical Properties of Friction Stir Welded Al–16Si–4Cu–10SiC Composite/Al–4Cu–Mg Alloy Joints

Effect of Tool Rotational Speed on Microstructure and Mechanical Properties of Friction Stir Welded Al–16Si–4Cu–10SiC Composite/Al–4Cu–Mg Alloy Joints

Influence of tool velocity ratio on force-torque and mechanical properties of friction stir welded 2050-T84 Al-Li alloy plates

Aluminium-lithium (Al-Li) alloy is the most prominent alloy used in the aerospace industry’s internal structure and wings due to its improved physical and mechanical properties. The present study introduces a novel investigation into the joining of Al–Li alloy 2050-T84 using friction stir welding (FSW) at different tool velocity ratios (TVR) of 0.6, 0.8, and 1, respectively (i.e., the amalgamation of various process parameters like tool rotational speed (TRS of 600, 1000, and 1400 rpm and traverse speed of 60, 120, and 240 mm min−1) and constant tool tilt angle (1.5°). A threaded taper tool was used for joining the Al–Li alloy 2050-T84. This work aims to ascertain the effects of varying tool velocity ratios (TVR; rotational speed/traverse speed) on macrostructure, grain size distribution in the nugget zone, and mechanical strength of the welded specimens. The experimental results reveal that increasing the tool velocity ratio increases the grain size and decreases the welded specimen’s ultimate strength and hardness values. Higher tensile strength (403.2 MPa), micro-hardness values (122.15 HV0.1), and joint efficiency (75.49) of welded specimens are achieved at low TVR (0.6), and ductile failure is observed in all welded samples. Additionally, it is noticed that the stirred zone size increased with increasing the velocity ratio.

Microstructure evolution and local mechanical properties of friction stir additively manufactured (FSAM) AA5083/AA6061/AA7075 gradient composite

The current study is focused on the successful fabrication and characterization of microstructure and properties gradient composite made of 3 mm thick sheets of AA5083-O, AA6061-T6, and AA7075-T6 alloys using friction stir additive manufacturing (FSAM) technique. Two combinations of four layered FSAM builds (6756 and 7567) were fabricated successfully without any major defects at the optimized process parameters of 850 rpm (tool rotational speed) and 55 mm/min (tool transverse speed). The material mixing, interfacial bonding features, microstructure evolution, and mechanical performance within the stir zones (SZ) were thoroughly examined using advanced characterization techniques. Electron backscatter diffraction (EBSD) analysis confirmed a gradient microstructure along the build depth in both FSAM builds, with average grain sizes decreasing from 52 μm (AA5083), 46 μm (AA6061), and 40 μm (AA7075) in base metals to ∼ 4–7 μm within the SZ. The remarkable grain refinement within the SZ was mainly attributed to the dominant presence of the continuous dynamic recrystallization (CDRX) mechanism. Texture analysis corresponding to pole figures (PFs) and orientation distribution function (ODF) plots reveals the crystallographic texture evolution along the build depth. The prevalent existence of B/ B‾ and C textures throughout all regions of the FSAM builds affirms the presence of ample shear strain during the FSAM procedure. Through thickness miniature tensile and microhardness tests depict the gradient in mechanical performance for both the FSAM builds along the build depth. Microhardness gradients in the range from ∼ 80 HV0.1 to ∼ 145 HV0.1 were observed along the build depth. The axial sample in the build direction shows appreciable strength (265 MPa and 224 MPa) and uniform elongation (28 % and 24 %) for 6756 and 7567 FSAM build, respectively. Furthermore, remarkable strain hardening behaviour corresponding to hardening capacity (Hc) and hardening exponent (n) was noticed for both the axial build samples compared to AA6061-T6 and AA7075-T6 base metals. These findings underscore the potential of FSAM in fabricating functionally gradient composite materials tailored to specific functional requirements.

Effect of Welding Conditions on Weld Zone Temperature and Mechanical Properties of Friction Stir Welded AZ61 Magnesium Alloy Sheet

Effect of Welding Conditions on Weld Zone Temperature and Mechanical Properties of Friction Stir Welded AZ61 Magnesium Alloy Sheet

Microstructural Characteristics and Mechanical Properties of Friction Stir Welded 2219 Aluminum Alloy Plate After Spinning and Heat Treatment

Microstructural Characteristics and Mechanical Properties of Friction Stir Welded 2219 Aluminum Alloy Plate After Spinning and Heat Treatment

Microstructure and mechanical properties of friction stir welded AZ31 magnesium alloy reinforced with ZrB2

Abstract Metal matrix composites (MMC) have advantages over polymer matrix composites such as high stiffness and strength, high-temperature resistance, better abrasion resistance, creep resistance, resistance to degradation by fluids, dimensional stability, and non-flammability. Metal matrix composites are used for various applications in the automotive, aerospace and sporting goods industries. The primary objectives of the current research work encompass the fabrication of Metal Matrix Composites (MMCs) AZ31 with 0.5%, 1.0% and 1.5% zirconium boride (ZrB2) nano-powder by the stir casting process, followed by welding through Friction Stir Welding (FSW). The metallographic analysis was carried out on the weldments of all cases. The macroscopic and microscopic analysis confirmed the defect-free weld joint. Tensile and hardness tests were conducted to study the mechanical properties of the materials. The tensile strength and the percentage of elongation increased with the percentage of ZrB2. But, after 1.0% addition of nano particles the strength decreased. The same pattern had been observed in both base and welded samples. The defect-free welding joints were fabricated with an efficiency of 79.1%, 79.7% and 77.7% for the materials with 0.5%, 1.0% and 1.5% nano powder, respectively. EIS and PDP tests were conducted in 3.5% NaCl to study the corrosion behaviour of base and welded materials. The corrosion tests on the base MMC samples showed that the corrosion resistance increased after the addition of ZrB2 nanoparticles. In addition, the corrosion resistance of all the welded samples improved compared with their respective base materials.

Effect on microstructure and mechanical properties of friction stir welded 5A06 aluminum alloy joints by deep cryogenic treatment

In order to improve the comprehensive mechanical properties of the welded joints of the 5A06 aluminum alloy, friction stir welded (FSW) joints were subjected to deep cryogenic treatment (DCT). The microstructure and mechanical properties were characterised using metallographic microscopy, x-ray diffractometer (XRD), energy spectrometer, microhardness tests, and tensile tests. The experimental results show that DCT refines the structure significantly due to the large temperature difference. This refinement results from an increase in Mg atoms within the α-Al solid solution through the precipitation of Al atoms, forming the Al3Mg2 phase. This enhancement in plasticity is achieved through dispersion distribution. Moreover, as the treatment time of DCT increases, the mechanical properties of the welded joint also improve significantly. The microhardness of the welding joint peaked at DCT3h, rising from 78.8 HV at DCT0h to 87.2 HV at DCT3h. Meanwhile, the tensile strength of the joint reached its maximum at DCT12h, rising from 358.7 MPa at DC0h to 385.3 MPa at DCT12h, representing a 7.4% increase. These experimental results underscore the significant impact of DCT on improving the welded joints.

Effect of material position and tool offset on the microstructure and mechanical properties of friction stir welded AA7075/AZ31B with ultrasonic assistance

The primary focus of this study is to analyze how changes in material position and tool offset affect the microstructure and mechanical properties of dissimilar alloys (AA7075/AZ31B) joints. The study specifically examines these effects in normal and ultrasonic-assisted friction stir welded (UVaFSW) aluminum and magnesium-based joints. The experiment showed that the sound weld was achieved only when the AA7075 plate was placed on the advancing side (AS). The metallographic analysis showed that the use of ultrasonic vibration increased the flow of material in the nugget zone (NZ) and improved the length of interpenetration at the interface. Moreover, the intermetallic compound (IMC) layer thickness decreased throughout the interface during UVaFSW, improving joint strength. The maximum ultimate tensile strength was obtained at 1 mm tool-off condition for UVaFSW, i.e., 112.40 ± 7.24 MPa. Ultrasonic vibrations reduced the IMC thickness by up to 78 % at the middle of the joint interface. The fracture surface showed the ductile fracture mode in the case of UVaFSW compared to the FSW process. The current study establishes the framework for optimizing and controlling the welding process of dissimilar AA7075/AZ31B alloys, which possess considerable potential for use in the aviation industry.

Microstructure Evolution and Mechanical Properties of Friction Stir Welded Al–Cu–Li Alloy

Microstructure Evolution and Mechanical Properties of Friction Stir Welded Al–Cu–Li Alloy

Analyzing the Influence of Microstructure on the Mechanical Properties of TIG Welded Joints processed by Friction Stir considering the sampling Orientation

The contribution of the microstructural arrangement to the mechanical properties of friction stir processed Tungsten Inert Gas (TIG) welded joints is reported in this work. The TIG-welded joints were subjected to a single pass of Friction Stir Processing (FSP). The friction stir processed joint was sampled transversally and longitudinally, and different tests were conducted and studied comparatively. The microstructural analysis showed refined grains with varying degrees. The mean grain size for the transversally sampled specimen was found to be 11.48 µm, while the longitudinally sampled specimen had varying mean grain size from 7.32 µm to 15.09 µm. The varying mean grain size of the longitudinally sampled specimen is caused by the staggered arrangement of the microstructure. The tensile properties and the microhardness of the transversally sampled specimen were lower than those of the longitudinally sampled specimen. The ultimate tensile strength of the transversally sampled specimen was found to be 87.88 MPa which is lower than that of the longitudinally sampled specimen (133.83 MPa). The microhardness of the longitudinally sampled specimen fluctuated between 30 HV and 80 HV while the transversally sampled specimen had a maximum microhardness of approximately 57 HV.

Reverse effects of pre-deformation and traverse speed on the mechanical properties of friction stir processed pure copper

In the present work, the effects of pre-strain and traverse speed on the microstructural evolution and tensile behavior of friction stir processed (FSPed) pure copper were investigated. In the samples without pre-deformation (0% samples), with the increment of the traverse speed from 100 mm min−1 to 200 mm min−1, the grain size decreased from 5.2 to 2.5 μm due to heat input domination. In the 60% pre-rolled samples (60% samples), interestingly, with an increase in the traverse speed (from 100 mm min−1 to 200 mm min−1), the average grain size increased from 2.4 to 6.8 μm owing to the domination of deformation degree. With the increment of speed from 100 mm min−1 to 200 mm min−1 in the 0% samples, the YS and UTS increased from 158.6 and 244.6 MPa to 190.7 and 253.9 MPa, respectively, due to decrement in the mean grain size. In addition, the increment of speed from 100 mm min−1 to 200 mm min−1 in the 60% samples reduced the YS and UTS from 177.9 and 261.7 MPa to 138.9 and 234.8 MPa, respectively, due to the increase in the mean grain size. In the 0% FSPed copper, by increasing the speed, the depth and size of dimples reduced, while, in the 60% FSPed samples, when the traverse speed increased, the dimples became larger.