Tool Tilt Angle Research Articles

Tensile strength of friction stir additive manufactured laminated AA 6061/TiC/GS composites

Abstract With the fast progress of industrial manufacturing, friction stir additive manufacturing has fascinated wide-ranging consideration in the industry due to high material consumption rate. Friction stir additive manufacturing (FSAM), a newly developed solid-phase additive manufacturing technique was employed to fabricate AA6061/TiC/GS composite. The process parameters like tool rotational speed, transverse speed, tool tilt angle and type of tools used in friction stir additive manufacturing were analyzed. Taguchi’s L16 orthogonal array and ANOVA method was used to find the optimum process parameters for the tensile strength. Development characteristics of stirred zone, recrystallization and mixing of reinforced particles will significantly improve the mechanical properties of the fabricated composites. Microstructural investigation and fractography was done by using optical microscopy and scanning electron microscopy (SEM). Corrosion, wear behavior and elemental analysis through EDS was also performed for the fabricated material. The maximum tensile strength of 385.74 MPa was attained under optimal parameters of the tool rotational speed 1,200 rpm, transverse speed 55 mm min−1, and tool tilt angle of 1° for scrolled tapered octagonal tool pin. The findings of the linear regression model showed a minor variance between model and experimental values. Prominent results of the experiment were compared by few other researcher’s findings working in similar area.

Development of Bamboo Based Nylon 66 Composite through Friction Stir Processing-An Attempt

The concept of developing a bamboo-based Nylon 66 polymer matrix composite is a relatively novel and very new technical attempt through friction stir processing (FSP). This innovative approach can create a composite material that strengthen the mechanical properties of bamboo and the versatility of Nylon 66. However, successful implementation requires careful consideration of FSP process parameters such us tool rpm, traverse speed, tilt angle and tool design. Among the processing parameters, the tool rpm shows the significant role for severe plastic deformation and temperature generation which leads to the achieving excellent bond. Therefore, in this present study attempt has made to develop the polymer matrix composite (nylon 66 and bamboo powder) using FSW process at a variant rotational speed of 300,400 and 500 rpm with the constant traverse speed of 25 mm min-1. The deformation behavior and the peak temperature evolved under the tool shoulder during the stirring motion is studied using COMSOL Multiphysics simulation. It is found that, the specimen processed with higher rpm (500rpm) shows the higher volumetric strain and the peak temperature and it is evident that with increasing rpm the higher amount of severe plastic deformation occurred. Initially the process parameters are optimized without bamboo powder on the nylon 66 plate of 6 mm thickness and found that the 500 rpm processed specimen shows the defect free. Prior to the actual FSP, the small keyways taken on the center of the nylon 66 plate in order to add the bamboo powders in it. Actual processing was done with bamboo powder after adding natural bamboo powder of size 50µm. The result reveals that, the bamboo powder has partially expelled out during the period of FSP. This complete study concedes that the processing parameters needs to be optimized and also bamboo added method need to be studied for the successful development of bamboo-based polymer matrix composite.

Effect of high pressure-low plasticity burnishing on the mechanical and microstructural behaviour of copper foil interlayered FSW aluminium alloys

Abstract This study delves into the impact of high pressure-low plasticity burnishing (HP-LPB) on the mechanical and microstructural behaviour of friction stir welding (FSW) joints, specifically involving AA5052 and AA6082 aluminium alloys. Notably, copper foil (CF) is introduced as a novel element in the HP-LPB process to enhance the weld strength. The experiments were conducted with the tool rotational speeds (TRS) of 1000, 1100, and 1200 RPM, each paired with the welding speeds (WS) of 20, 25, and 30 mm min−1, and tool tilt angle (TTA) of 0°, 1°, and 2°. Mechanical behaviour is assessed through tensile testing along with microhardness measurements, revealing the advantages of HP-LPB with CF in enhancing joint strength and toughness. The microstructural analysis reveals the dissolution of precipitates, highlighting the influential role of copper foil in the improvement of joint efficiency. From the weld without a CF interlayer, a maximum tensile strength of 188 MPa was achieved at a TRS of 1200 RPM, WS of 25 mm min−1 and TTA of 2°. The post-processed FSW sample interlayered with copper foil, exhibited an improvement in joint efficiency by 87% at the optimum process parameter. This research demonstrates that the use of copper foil interlayers combined with HP-LPB treatment can substantially enhance the mechanical properties and structural integrity of FSW aluminum alloys, offering a valuable solution for advanced industrial applications.

Influence of tool traverse speed on mechanical properties and fracture morphology of friction stir welded pure copper butt joints

The key goal of this research was to study the effect of the traverse speed of a tool on microstructural changes, mechanical properties and fracture morphology of pure copper butted weld joint by friction stir welding technique. In this study, other parameters like tool rotational speed (1000 rpm), axial force (4.2 kN), tilt angle (0˚) and tool offset (0 mm) were fixed. A cylindrical tool with a non-threaded tapered pin was used to fabricate the weld joints. All the weld joints produced by varying the traverse speeds (11, 20 and 24 mm min−1) were defect-free. It was noticed that the grains in the stir zone were tiny, well distributed and homogeneous at 24 mm min−1 owing to the adequate heat generation and complete intermixing of material in the stir zone. The utmost tensile strength of 187 MPa was achieved by the welded joint attained at 24 mm min−1. It was observed that a densely populated dimple structure enhances the joint ductility in the case of 24 mm min−1.

ANN modeling and optimization of friction stir welding performance for AA6061 and AA5083 alloy joints

This research focused on the characteristics of the AA6061/AA5083 alloy joints which are fabricated by the friction stir welding (FSW) technique. The impact of FSW parameters such as tool tilt angle, pin depth, and tool geometry on the mechanical properties and fractographic characteristics were studied. Ultimate tensile strength (UTS), hardness (HBN), and specific wear rate (SWR) were examined for characterization while fractography analyses were done using scanning electron microscopy. Taguchi-Grey relational analysis (GRA) was employed to execute multicriteria optimization and recognize the best grouping of parameters. The optimized values attained from this analysis were 259.2 MPa for UTS, 94.9 HV for HBN, and 0.0819 m³/Nm for SWR. The analysis of variance (ANOVA) results derived from the GRA revealed that tool geometry exerted the most significant influence (39.79%) on output factors, followed by pin depth (24.90%) and tilt angle (24.26%). To enhance the predictive accuracy of the output responses, an artificial neural network (ANN) model was developed utilizing the Levenberg-Marquardt (LM) algorithm. The optimized ANN architecture, configured as (3–10–3), exhibited robust regression analysis outcomes, showcasing correlation coefficients ( R) of 0.99999, 0.99967, and 0.99994 for the training, validation, and test datasets. The overall R-value, computed at 0.99958, affirmed high conformity between experimental and predicted values.

Experimental optimization of the FSW parameters to weld the dissimilar Al- and Cu-alloys by using additives at their joints

Friction stir welding (FSW) stands as a promising technique for joining materials, offering advantages over conventional methods. This study investigates the influence of tool tilt angle, rotational speed and profile on welded joint characteristics using a design of experiment (DOE) approach. The research objective aims to determine optimal parameter combinations for improved mechanical properties. Methodology entails the systematic variation of tilt angle, rotational speed and tool profile in a DOE setup, with subsequent FSW of samples. Mechanical testing, including tensile, bend and hardness tests, is conducted on 24 samples, with scanning electron microscope (SEM) and microstructure analysis on two specimens. Results reveal that higher tilt angles, rotational speeds and threaded profiles yield increased tensile strength but decreased ductility. Similarly, bend tests show higher fracture loads but reduced deflection before fracture under these conditions. Hardness tests indicate elevated hardness in welded areas, with variations based on input parameters. Main findings highlight the importance of parameter optimization for desired mechanical properties. Lower tilt angles and rotational speeds promote smoother material flow and uniform heating, resulting in consistent microstructure and hardness distribution. In conclusion, this study provides valuable insights for optimizing FSW parameters to achieve desired mechanical properties in welded joints. The combination of a 2° tilt angle, threaded tool profile and 1500 rpm rotational speed demonstrated the highest tensile strength, while a 1° tilt angle, cylindrical tool profile and 1000 rpm rotational speed yielded highest ductility.

Experimental investigation into friction stir welding of AA6061-T6 and magnesium AZ31B alloy using copper backing plate

Aluminium-magnesium alloys are lightweight and possess superior properties, making them ideal for applications in aerospace, railway, automotive, and marine structures. However, these alloys are challenging to fabricate using traditional fusion welding due to various metallurgical issues. This study investigates the feasibility of joining 3 mm thick dissimilar alloys of aluminium AA6061-T6 and magnesium AZ31B using the friction stir welding (FSW) process with copper as a backing plate. The effects of FSW process parameters, including tool rotational speed (380, 545, 765 rpm), weld speed (20, 31.5, 50 mm min−1), and tilt angle (1°, 2°, 3°), on tensile properties were examined using Taguchi-based grey relational analysis. Temperatures were recorded during the FSW process under different conditions on both sides of the joint. The highest tensile strength of 130.72 MPa, with a joint efficiency of 67.85%, was achieved at a tool rotational speed of 765 rpm, a welding speed of 50 mm min−1, and a tilt angle of 2°. Analysis of variance (ANOVA) for the grey relational grade indicated that the tilt angle had the highest percentage contribution of 43.60%. This study demonstrates the significant influence of FSW parameters on the mechanical properties of aluminium-magnesium joints and highlights the optimal conditions for achieving high joint strength and efficiency.

A novel approach for zero material loss (zero flash) and uniform cross-section during friction stir welding of dissimilar thickness Cu and Al alloys

A novel approach for getting a uniform weld cross-section and flash-free joint with the help of friction stir welding (FSW) is implemented. The influence of the tool tilt angle and rotational speed on the macrostructure, microstructure, and mechanical properties was investigated. Mechanical characterization techniques like an optical microscope, FESEM, profilometer, tensile test, bent test, and XRD analysis were used to evaluate the joint properties. A maximum tensile strength of 108.91 MPa was achieved, which led to a joint efficiency of 96.38 %. A maximum bending angle of 107° was achieved for samples S5 and S6. The Al/Cu mixed region in the stir zone displayed a maximum micro-hardness of 152.26 HV whereas a minimum micro-hardness of 33.57 HV was achieved in the HAZ along aluminium side. Welds prepared at a rotational speed of 540 RPM and a tool tilt angle of 4.5°results in an almost flash-free joint.

Failure evaluation on tailor made aerospace aluminum alloys via underwater friction stir welding employing predictive machine learning technologies

Employing tailor-made alloys with uneven thickness achieves light weighting, a critical issue for reducing emissions, leading to lower aircraft pollutants and fuel costs. The research utilizes advanced machine learning techniques such as Gaussian process regression (GPR), artificial neural networks (ANN) linear regression (LR), and support vector machines (SVM) to predict the ultimate tensile strength of underwater friction stir welding of AA6082-T6 and A2219-T83 tailor-made joints. The models have been evaluated with an assortment of kernel functions, including the polynomial kernel (PK), the radial basis function (RBF), and the Pearson VII universal kernel (PUK). To acquire experimental data, we used a Central Composite Design (CCD) technique, incorporating various factors in the process encompassing tool tilt angle (TA), rotating speed (RS), and welding speed (WS). The SVM radial basis function model (SRBP) had a maximum correlation coefficient of 0.9995 and a minimum root mean square error value (RMSE) of 0.5433 in the training set and 0.6271 in the test set. The ANN model predicted the UTS with an error margin of 0.21%, while the SRBP model showed a 0.52% error, and the LR model exhibited a significantly higher error of 7.73%. A peak tensile strength of 252.98 MPa was recorded in the S20 specimen, accounting for 85.61% of the base metal’s (AA6082 T6) strength. A reduced acute tearing ridge indicates petite, shallow dimples due to the inherent cooling. Through the analysis of metrics and residuals, high accuracy rates were observed when employing the ANN and SRBP models to predict mechanical traits.

RETRACTED ARTICLE: Investigating the strength of butt-welded joints of AA6082 and AA5052 alloys through friction stir welding; the impact of tool tilt angle and feed rate

We, the Editors and Publisher of the Journal of Adhesion Science and Technology, have retracted the following article: Investigating the strength of butt-welded joints of AA6082 and AA5052 alloys through friction stir welding; the impact of tool tilt angle and feed rate. Journal of Adhesion Science and Technology, https://doi.org/10.1080/01694243.2023.2253631. Bhiksha Gugulothua, Rajasekaran Saminathan, A. Pradeep, Ankit Sharma, S. Vijayakumar, Prabhu Paramasivam, and N. Srinivasa Rao. (2023). Since publication, concerns have been raised by a third party about the integrity of the data presented in the article, as well as potential authorship concerns. When approached for an explanation, the authors have been unable to provide their original data to verify its authenticity. In addition, the authors have not fully responded to our questions regarding the process of the research conducted. We have been informed in our decision-making by editorial policies and the COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

Unveiling the Potential of Friction Stir Welding for Seamless Metal Joining

Friction Stir Welding (FSW) has revolutionized metal joining in manufacturing by offering robust joints without defects. This study examines FSW using specific parameters and evaluates its impact on mechanical properties and microstructure. Through rotational speed (2192 RPM), welding speed (36.3 mm/minute), tool tilt (3.4°), and concave shoulder angle (9°), FSW was applied to predetermined metal materials. Impact and Vickers tests were conducted post-welding to assess toughness, surface hardness, and microstructural changes. Results highlight the significant influence of FSW parameters on material properties, providing insights for optimizing efficiency and quality in the manufacturing industry. The study's findings contribute to addressing knowledge gaps and advancing FSW applications in industrial settings. Highlight: Precise Parameters: Control for strong joints in manufacturing. Toughness Evaluation: Assessing joint resilience under dynamic loads. Industry Optimization: Enhancing efficiency and quality in metal joining processes. Keywoard: FSW, Manufacturing, Mechanical Properties, Optimization, Impact Testing

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.

Optimizing friction stir welding of AA7075 and AA8090 aluminum alloys: a desirability-driven investigation into mechanical and microstructural enhancement

This research explores the multifaceted analysis of a friction-welded joint, employing Central Composite Design of Response Surface Methodology. The study integrates microstructural investigations and fracture analyses to explain the effect of process parameters on mechanical properties. The optimum settings for Friction Stir Welding of AA7075 and AA8090 were determined by assessing desirability indices. These settings comprised a tool rotation speed of 1927.7 rpm, a tool travel speed of 35 mm min−1, and a tool tilt angle of 0.9°. This specific combination yielded a noteworthy combined desirability index of 0.79, considering both Ultimate Tensile Strength (UTS) and Tensile Elongation (TE). Microstructural examinations revealed distinct characteristics in the Heat-Affected Zone (HAZ), Thermo-Mechanically Affected Zone (TMAZ), and Nugget Zone (NZ). Notably, fine grain structure in the NZ was attributed to the stirring effect created by the tool pin. Fracture analyses indicated ductile fractures, with dimple size variation correlating to tensile strength. Lower dimple density in low-strength joints suggested insufficient material mixing during welding. The maximum tensile strength sample exhibited a high dimple density. These findings contribute to a comprehensive understanding of the welding process’s influence on microstructure and fracture characteristics, providing valuable insights for optimizing mechanical properties in friction-welded joints.

The Influence of Tool Tilt Angle on the Friction Stir Welding Characteristics of Wrought Magnesium Alloy Plates

The Influence of Tool Tilt Angle on the Friction Stir Welding Characteristics of Wrought Magnesium Alloy Plates

Application of friction stir surface treatment for modification of peripheral coarse grain structure and mechanical properties of AZ31 Mg alloy

The presence of peripheral coarse grains (PCG) in the microstructure of extruded products is considered one of the causes of decreased mechanical properties. Such microstructure has been observed at the periphery of extruded AZ31 Mg alloy. This research aims to achieve a refined and homogeneous microstructure at the structure of extruded bars of AZ31 alloy using pinless friction stir processing (FSP). Up to six passes of FSP using pinless tools with different shoulder surface geometries were conducted. Tools with varying diameters of 12, 15, and 22 mm were used to investigate the effect of shoulder geometry. The rotational speed and traverse speed of the tool were set at 900 rpm and 70 mm/min, respectively. The tool tilt angle was also set to 3°. The effect of the tool geometry on the metallurgical and mechanical properties was investigated using metallography tests, microhardness testing, tensile testing, and fracture testing. According to the results, it was found that reducing the diameter of the tool and using featured tool can lead to homogenization and reduction of the average grain size in the processed samples, increasing the microhardness compared to the primary sample. It was also observed that mechanical properties were improved with the increase in the tool diameter due to the improved quality of the processing area. For samples processed with a 22 mm diameter tool, the final strength reached 242.7 and 248.81 MPa, respectively, for the simple and featured tools.

Friction Stirs Processing - State of The Art Process to Fabricate Metal Matrix Composites

Friction stir processing(FSP) is the solid state method to fabricate the surface metal matrix composites(MMC). This process has been derived from the concept of Friction stir welding. As this process is performed in solid state, many defects related to phase transformation can be avoided. As this process is done below the melting point temperature of metal or alloy, it is easier to control the process. Machine variables (tool rotational speed, tool traverse speed, tool tilt angle etc.), tool design variables (diameter, profile and height of probe and shoulder of the FSP tool), and material properties are the main process variables to perform FSP in order to fabricate Metal matrix composite. In addition to these variables number of passes, tool traverse patterns, reinforcement particles’ content and its’ types also can be considered as process variables. Tribological properties’ comparison can be done between alloy and MMC fabricated by FSP for different combinations of process parameters. Microstructural study also can be carried out in order to see the effects of above process parameters. In this paper the above aspects are summarized and performance assessment done by various researchers has been covered.

Efficiency Improvement of Friction Stir Welding Parameters on AZ91 Magnesium Alloy Joints

Abstract: Friction Stir Welding (FSW) is a solid-state welding that permits an intensive formof parts and geometries to be welded with great nature of joints. The use of high-quality Magnesium alloys is extending in shipbuilding industry, particularly for the advancementof naval warships, cruise ships, littoral surface craft and merchant ships. FSW advancementhas been seemed to have various focal points for the exploitation of Magnesium alloys structures, as it is a minimal effort welding process. The objective is to come across the optimum levels of the process parameters in which it yields maximum tensile strength andbetter hardness. A three-factor, three-level design is utilized for optimizing the FSW process parameters and a Taguchi L9 orthogonal array experimental set up is used to anticipate the responses. The system parameters considered are Rotational speed, Transverse speed and the Tool tilt angle. The Friction stir welding is processed for butt joining of Magnesium alloys (AZ91) plates with 6 mm thickness. Tensile testing is attempted on dog-bone kind test specimen for Magnesium alloys. Analysis of Variance (ANOVA) has been used to analyze the effect of different parameters regarding the responses. The microstructural attributes of the welded segments, including base metal, heat affected zone (HAZ), Thermo Mechanically Affected Zone (TMAZ) and Stir Zone (SZ) are examined through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis carried out to quantify the chemical element allocation at the weld interface. The observed optimum condition for Magnesium alloys (AZ91) is 560 rpm, 60 mm/min and 1 degree.

State-of-the-art survey of literature for finding an effective solution to mitigate the exit-hole defect in friction stir welded samples

Friction stir welding is a solid-state welding process among the most important processes used for welding materials that the conventional welding process cannot weld. The joining of two metals occurs by heat generated due to the friction between the non-consuming rotating tool surface and workpiece. This technology is extensively used in the automobile, railway, maritime and aerospace industries. There are some defects that occurred in this process such as the tunnel, kissing bond, incomplete root penetration, excessive flash and void, those can be overcome by modifying the process parameters namely tool rotational speed, welding speed, downward force, shoulder diameter, shoulder geometry, tool pin geometry, tool pin diameter, tool pin length and tilt angle. The inevitable defect is the exit-hole left after the retraction of a rotating tool at the end of the weld cycle. The present work reviews different repair techniques for the exit-hole of the welded joints. This article discusses various exit-hole repairing techniques pertinent to the method, process parameters, material, plate thickness and the defect that emerges using these techniques. The current survey also presents a few future research opportunities in this field that can be carried out to mitigate the exit-hole defect.

A novel zero tool defect accelerated friction stir thin sheet welding technique for automotive light-weight structural component fabrication with dissimilar material

Frequent tool failure and rupturing pose significant challenges in friction stir welding (FSW) of thin dissimilar material sheets with diverse thermal and mechanical properties. These issues exacerbate at higher welding speed (ν), demanding greater precision in welding methodology. This paper presents a novel approach to weld 300 μm thin SS304 and 500 μm thick commercially pure aluminum sheets at ν up to 2400 mm/min using H13 tool without wear, obviating the necessity for expensive high-strength tool materials. Furthermore, the use of a pinless tool negates the requirement for an additional pinhole filling step, which is a prevalent challenge associated with pinned tools. The study unveils that higher tool tilt angle (α) reduces flash formation, leading to a higher effective weld thickness, thereby enhancing weld strength. The increased material extraction (2.048 mm3) from the weld center and higher heat generation (7.6%) compared to the pinless tool imposes a speed limit of 300 mm/min for the pinned tool. The thicker layer (4.9 μm) of inter-metallic compounds (IMC) formed at lower ν showed maximum joint strength (70.03% of base Al). The fracture behavior indicates cleavage facet formation becomes more frequent at higher ν, diminishing joint ductility. With a distortion-free, high lap shear strength and enhanced ν, this novel joining method meets the needs of industrial mass production.

Grey-Taguchi Approach for Optimizing FSW Parameters in Joining AA6262 and AA5083 Alloys

T his study concentrates on the friction stir welding (FSW) joining of dissimilar AA6262 and AA5083 plates. Four input parameters, namely tool rotational speed (TRS), welding speed (WSP), tool tilt angle (TTA), and pin depth (PDP) are chosen to analyze the output responses of tensile strength (UTS), hardness (HBN), and wear rate (WTR) in welding. The primary objective is to optimize the variables of the FSW process for AA6262 and AA5083 alloys using a combination of Taguchi and Grey Relational Analysis (GRA) methods, while also comprehending the correlations among process variables through the application of these two methods. Utilizing the Taguchi approach, L27 orthogonal array is constructed for conducting FSW experiments. After this, the multi-objective optimization challenge is streamlined into a single-objective optimization task by leveraging the grey relational degree. The significance and impact of the distinct variables are elucidated through the application of Analysis of Variance (ANOVA). Confirmation tests and predictive analysis are performed to validate the optimal variables, which are then compared against the acquired outcomes. The results highlight the welding speed as the paramount parameter, exerting substantial influence over the output responses of the welds in contrast to the other variables under examination. The application of the Grey-Taguchi methodology yields enhancements in Tensile Strength (245.23 MPa) and Hardness (99.2 Hv), while concurrently decreasing the Wear Rate (0.00456 m3/Nm). Furthermore, the Grey Relational Grade exhibits an advancement of 0.1312. These findings collectively signify an increased operational efficiency in the welding process, particularly for dissimilar alloys.