Pin Profile Research Articles

Role of Pin Profile and Offset in Interfacial Characterization and Mechanical Behavior of Dissimilar Friction Stir Welded T-Lap Joints

Role of Pin Profile and Offset in Interfacial Characterization and Mechanical Behavior of Dissimilar Friction Stir Welded T-Lap Joints

Multiphysics computational modelling and experimental analysis of friction stir welding of aluminium alloy metal matrix composites (AAMMCs)

Friction stir welding is a modern method for fabricating aluminium alloy metal matrix composites (AAMMCs) that significantly enhance the properties of the parent materials. In this study, Al2O3 particles were incorporated into a 6061-T6 aluminium matrix. Experimental and numerical modeling provided in-situ observations of particle-aluminium matrix mixing in the weld stir zone (SZ). Two different pin profiles, threaded and square, were used to fabricate the AAMMC joints. The threaded pin profile resulted in uniform dispersion and a homogeneous distribution of Al2O3 particles within the aluminium matrix. In contrast, the square pin profile led to defects in the SZ and a non-homogeneous particle distribution. The volume fraction mixing of the AA6061-T6 matrix and Al2O3 at the workpiece/tool interface from top to bottom was analyzed using a level set technique. Experimental results showed effective mixing of Al2O3 particles in the AA6061-T6 matrix with the threaded pin profile, resulting in a defect-free joint, uniform particle distribution, and ultra-fine grain refinement, with grain sizes reduced to 4.19 µm. The main shear texture components observed in the threaded pin joints included B/B̅ and C, along with deformed and recrystallized texture components such as Copper {112} 〈111〉, Brass {110} 〈112〉, Goss {011} 〈100〉, Cube {001} 〈101〉, and P {011} 〈112〉 . Additionally, joints fabricated using threaded pin profiles exhibited significantly higher tensile strength (up to 270 MPa) and microhardness (average of 120 HV0.2) compared to those with square-shaped pin profiles, which showed lower values of 240 MPa and 105 HV0.2, respectively. Thus, AAMMC joints made with threaded pins demonstrate ultra-fine grain refinement, increased high-angle grain boundaries, enhanced recrystallized texture components, and improved mechanical properties, resulting in superior overall joint performance.

Friction stir process parameters optimization in the fabrication of agate particle reinforced AA6061-T6 aluminum alloy surface composite

The main objective of this study was to optimize the friction stir process parameters to fabricate agate particle reinforced AA6061-T6 Aluminum alloy surface composite for hardness and tensile strength. The surface composite samples were made using a CNC milling machine based on Taguchi’s mixed L16 orthogonal array. The process parameters such as tool rotational speed, traverse speed, percent of reinforcement, number of passes and pin profiles were selected in this study. The optimal properties for the developed surface composite were obtained when surface composites having 18% reinforcement were fabricated by a two-pass FSP using a squared pin tool with a rotational speed of 1400 rpm and traverse speed of 60 mm/min. At the optimal process parameters, the tensile strength and hardness of the fabricated surface composite were found to be 312.23 MPa and 74.82 HRB respectively. ANOVA analysis performed at a 95% confidence level revealed that all process parameters were significant and the contribution of the number of passes on the properties of surface composite was higher than other process parameters. Microstructural analysis revealed that medium rotational speed and high traverse speed produced a uniform distribution of agate particles which helped to improve the properties.

Effects of electrochemical corrosion on retrogressed and different reaged friction stir welded AA7075-AA6082 dissimilar welds

ABSTRACT The research is primarily to study the microstructure, tensile and electrochemical corrosion behaviour of friction stir welded AA7075-T651-AA6082-T6 dissimilar welds, subjected to retrogression and reaging at 280⁰C for 5 min followed by aging at 110⁰Cfor 1 , 5 , 10 and 24 h respectively. The AA7075-AA6082 welds were made using optimum parameters such as feed rate 80 mm/min, tool rotation speed 980 rpm, and tilt angle 2 o . The alloys of 100 × 50 × 6mm³ plates were welded with a conical tapered tool pin profile. Further, the welds were scanned for potentiodynamic polarisation with a 3.5 percentNaCl solution. Optical metallographic (OM) images were revealed to determine morphology andcorrelate with the measured corrosion rate. Here, the dissimilar friction stir weld AA7075-AA6082-aged for 5 h had an ‘Ultimate tensile strength’ (UTS) of 269.73N/mm2 due to coherent precipitates. Moreover, at 24 h, the lower tensile strength of 226.06 N/mm2 was observed, due to coarser precipitates across the AA7075-AA6082 weld cross-section. Due to over-aged coarse precipitates, the corrosion rate of 6082BM and weld metal had increased to 5.110e + 003mpy and 1.010e + 003mpy. Under other aged conditions, the corrosion rate was decreased below 0.001mpy.

Thermal and Mechanical Investigation of Friction Stir Welding with Disparate Materials AA6061 and AA7075

Background:: The primary objective of this study is to assess the impact of welding conditions on the mechanical properties of friction stir-welded butt joints created from two distinct aluminium alloys, namely, AA6061 and AA7075. Friction stir welding (FSW), known for its innovation and low-energy solid-state bonding technique, was employed in this research. Methods:: FSW experiments were carried out on both AA6061 and AA7075 alloys using a computer numerical control (CNC) machine. The selection and design of the tool geometry were meticulous, with an emphasis on new pin profiles that are nearly flat at the weld contact point. Precisely, four distinct tool geometries were machined from HC-HCr (High carbon, high chromium steel): Circular, Square, Tapered third, and Triangular. Critical process variables that significantly influence weld quality include rotation speed (800 rpm-1400 rpm) and traverse speed (12 to 25 mm/min). These variables were carefully optimized to achieve flawless welds. During the friction stir welding process, the nugget zone undergoes significant deformation, leading to the formation of a new microstructure that substantially impacts the mechanical properties of the joint. Results:: This study comprehensively investigates the thermal and mechanical properties of friction stir welding using aluminium alloys AA6061 and AA7075, considering various tool shapes. Among the four tool shapes employed, two were found to yield higher hardness values (referred to as BH). Notably, the square-shaped tool produced the highest temperature, reaching up to 690ºC, as determined by thermocouple readings. Based on the findings, the optimal FSW parameters for enhancing hardness involve an axial feed and spindle speed of 800 rpm combined with a feed rate of 15 mm/min. These parameters were identified as crucial for achieving the desired mechanical properties in the friction stir-welded joints. Conclusion:: This study presents new developments in FSW technology, which may have patent implications.

Influence of tool pin profiles on the mechanical and microstructural properties of a single-pass friction stir-welded AA7075-T6 aluminium alloy

ABSTRACT This research explores the influence of distinct tool-pin geometries on the mechanical and microstructural characteristics of single-pass friction stir-welded (SP-FSW) joints in 6 mm-thick Al-alloy (AA7075-T6) plates. The study involves three distinctive tool pin profiles: a cylindrical tool pin (M1), a square tool-pin (M2), and a conical tool-pin (M3), all featuring a scrolled shoulder, which was utilised to create the welded joints, ensuring that fully penetrated and defect-free welds were achieved by maintaining a constant tool rotation speed of 800 rev/min and a travel speed of 50 mm/min. Notably, the average grain size within the stir zone (SZ) of the M2 joint was smaller than the M1 and M3 joints. Furthermore, the microhardness of the M2 joint exhibited higher values in the thermo-mechanically affected zoneand SZ in contrast to the M1 and M3 welded joints. Additionally, the results of the tensile tests revealed joint efficiencies of 46.2%, 60.5%, and 51.1% for the M1, M2, and M3 joints, respectively. The ductility of M1, M2, and M3 welded joints was 8.68%, 11.3%, and 11.9%, respectively. The fractured tensile sample was characterised by SEM and micro-cracks and large dimples with brittle fractures were observed in all M1, M2, and M3 welded joints.

Process parameters settings of friction stir welding using multi-response optimization for aluminum alloys

The defense and aerospace industries utilize the AA2050, an aluminum-lithium alloy of the third generation. Principal component analysis (PCA) and Taguchi-grey relational analysis (GRA) are utilized in this study to enhance the process constraints for friction stir welding (FSW). The quality of the weld can be influenced by various process factors such as the speed at which the weld is traversed, the speed at which the tool is rotated, the angle at which the tool is tilted, the diameter of the shoulder, and the shape of the tool pin. The combination of PCA and the well-known Taguchi-GRA approach enables the objective estimation of response weights. Here, a Taguchi L16 orthogonal array was designed, and sixteen tests were carried out using it. These experiments were conducted with various assessments including tensile strength, yield strength, elongation percentage, hardness of the weld zone, bending load, etc Through the utilization of Taguchi-GRA-PCA analysis, the most suitable process parameters were identified as a traverse speed (TS) of 160 mm min−1, a rotating speed (RS) of 900 rpm, a tilt angle (TA) of 2 degrees, a shoulder diameter (SD) of 16 mm, and with a straight square tool pin profile (TPP). ANOVA revealed the relevance of all five characteristics, with rotational speed being the most influential, accounting for 43.56% of the entire result. A confirmation experiment done under ideal conditions revealed a significant improvement in total weld quality of 19.06%.

Mechanical Properties Enhancement in Friction Stir Processed AA2024 Alloy through Pin Profile Optimization

Mechanical Properties Enhancement in Friction Stir Processed AA2024 Alloy through Pin Profile Optimization

Optimization of parameters and formulation of numerical model employing GRA–PCA and RSM approach for friction stir welded Ti–6Al–4V alloy joints

In this work, an endeavour was made to determine the impact of the tool’s shoulder diameter, pin profile, rotational and traverse speeds on the mechanical properties of the friction stir welded namely Ti–6Al–4 V alloy joints. A total of 21 experiments were carried out based on the central composite design (CCD) concept of response surface methodology (RSM). A quadratic regression based numerical model was formulated to ascertain the relationship amidst the parameters of FSW process and the mechanical properties of the fabricated Ti alloy joints. Analysis of variance (ANOVA) was employed to confirm the importance of parameters and their interactive impacts. Optimized process parameter combinations were ascertained by grey relation based analysis (GRA) was coupled together with principal component analysis (PCA), a hybrid based approach. Single score of GRG based response was determined and GRG scores were ranked for all experiments. 1st rank was attained by the experiment no. 20 possessing a GRG score of 2.9989. Optimized values of 25 mm shoulder diameter having a taper cylindrical pin geometry employed at a tool traverse speed of 40 mm min−1, rotational speed of 1400 rpm resulted in the generation of flaw free Ti alloy joint possessing a largest tensile strength of 809.8 MPa, yield strength of 778.7 MPa and percentage of elongation of 6.9%. SEM based fractography of Ti alloy joint specimens announced that taper cylindrical pin geometry along with 25 m shoulder diameter of employed tool have an inevitable part in generating frictional heat in ideal volumes and a perfect stirring action during FSW process.

Severe Plastic Deformation of Al–Mg–Si Alloy: The Role of Threaded Pin Profiles in Achieving Grain Refinement Through Friction Stir Processing

Severe Plastic Deformation of Al–Mg–Si Alloy: The Role of Threaded Pin Profiles in Achieving Grain Refinement Through Friction Stir Processing

Effect of Friction Coefficient in Friction Stir Welding of B4C Reinforced AA5083 Metal Matrix Composites and Use of Fuzzy Clustering Technique for Weld Strength Prediction

The friction stir welding (FSW) method was used to weld B4C reinforced AA 5083 metal matrix composites in this study. By coating titanium nitride (TiN), aluminium chromium nitride (AlCrN), and diamond-like carbon (DLC) to a thickness of 4 microns, three FSW tools with square pin profiles were developed and the friction coefficients of 0.69, 0.32, and 0.2 were maintained. At three levels, the process factors such as tool rotating speed, transverse feed, and axial force were examined. For each tool, 15 samples were made using the central composite design. The influence of the friction coefficient on ultimate tensile strength, microstructural features, and tool condition was studied, and the flower pollination algorithm (FPA) technique was used to find the best process parameters for obtaining maximum ultimate tensile strength of FSW joints. The improved tensile strength of FSW joints was verified using a validation test. The coating has a considerable influence on the ultimate tensile strength, microstructure, and tool condition, according to the results of the tool’s friction coefficient. The results on the prediction of strength using the fuzzy clustering technique showed that the technique is effective in predicting the tensile strength values, with the root mean square error (RSME) of TiN, AlCrN, and DLC being 0.0027, 0.0016, and 0.0015, respectively, and the low RSME indicating that the prediction based on the fuzzy subtractive clustering technique is perfect and effective.

Effect of friction stir processing parameters on mechanical properties of Al8011/CeO2/SiC/RHA metal matrix composite

ABSTRACT In this research work, the FSP route opted to fabricate the metal matrix composite (MMC) on the surface of an aluminium 8011 alloy sheet by incorporating different volumetric compositions of silicon carbide (SiC) and cerium oxide (CeO2) with a constant 5% volumetric composition of rice husk ash (RHA). The fabrication process was based on the L27 design of experiments. Taguchi-coupled grey relational analysis (GRA) was employed for process optimisation with four factors: tool rotation speed, tool travel speed, reinforcement volume, and tool type, each with three levels, while tensile strength and micro-hardness were taken as the response variables. The optimal parameter setting for fabrication of Al8011 MMC was 600 RPM of rotational speed (level 3), 20 mm/min travel speed (level 1), reinforcing volume% (level 2), and straight cylinder pin profile (level 1). The corresponding values of the optimised response variables were 181.91 MPa tensile strength and 139.09 Hv microhardness. The tensile strength and microhardness of base Al8011 were found to be 175.77 MPa and 92.72 Hv, respectively. Meanwhile, the microstructure of the optimal FSP-processed MMC was analyzed through the scanning electron microscopy (SEM) technique, which confirmed a homogeneous distribution of reinforcing agents and refined grain structure.

Fabrication of tungsten inert gas-welded dissimilar aluminium joints using different friction stir processing tools through response surface method

ABSTRACT AA6061-T6 and AA7075-T6 materials find wide application in manufacturing industries due to their excellent engineering properties. Fusion welding generates solidification cracks, high residual stresses, and brittle intermetallic compounds that degrade joint qualities. To solve these difficulties, friction stir processing (FSP) is frequently employed, which improves joint properties through local microstructural refinement. In this study, the combined effect of FSP parameters, namely tool pin profile (TPF), tool rotation speed (TRS), and travel speed (TS), on tungsten inert gas (TIG) weld properties was investigated. Response surface methodology (RSM)-based mathematical models were developed to predict responses, namely ultimate tensile strength (UTS), impact toughness (IT), microhardness (MH), and residual stress (RS). The optimal FSP parameters were determined through the desirability function technique. Post-FSP increased the UTS, IT, and MH of TIG welds by 71.51%, 95.40%, and 72.46%, respectively, and decreased the RS by 58.46%. ANOVA findings exhibited that TPF was the most influential parameter, followed by TRS and TS. The dissimilar aluminium TIG+FSP joints showed an optimal UTS of 282.08 MPa, an IT of 17.32 J, a MH of 121.48 HV, and an RS of 22.09 MPa when using a TRS of 1108.49 rpm and a TS of 37.74 mm/min with a THF pin.

Thermal and mechanical characterisation of friction stir welded dissimilar aluminium alloys

The influence of thermal properties on the friction stir welded (FSW) dissimilar aluminium alloys at different tool rotational speeds and tool pin profiles was studied. AA 5083 H111 and AA 6082 T6 of 6 mm aluminium alloy plates are welded by varying the process parameters. The influence of heat generation and heat transfer in the joint efficiency of the weldments are characterised. Heat flow and heat flux for various tool rotation speeds generated between the tool shoulder and workpiece are calculated and analysed. The rate of heat distribution during welding is evaluated by calculating the thermal diffusivity of AA5083 H111 and AA6082 T6. Microhardness test helps to comprehend the influence of the parameters over the mechanical property of the weldments. The results revealed that the thermal characterisation clearly illustrates that an increase in tool rotation speed directly amplifies the heat flow and heat flux in weldments. However, AA 5083 H111 and AA 6082 T6 for varying temperature and reveals that 580°C possessed higher thermal conductivity for AA 6082 T6 (260 W/m°C) and AA 5083 5083 H111 (160 W/m°C), thermal conductivity for AA 6082 T6 (1260 J/Kg°C) and AA 50835083 H111 (1225 J/Kg°C) and thermal Diffusivity was 5.2029 × 10−5 (m2/s) for AA 5083 H111 and 7.61819 × 10−5 (m2/s) for AA 6082 T6.

Underwater friction stir welding of ultrafine-grained laminated composites produced through accumulative roll bonding process

In this work, ultrafine-grained (UFG) plates of AA2024/AA5083 laminated composite with alternating layers of heat-treatable aluminum AA2024 and strain-hardening aluminum AA5083 were fabricated through accumulative roll bonding (ARB) technique and were subsequently joined using underwater friction stir welding (UFSW). Friction stir welding (FSW) is a solid-state welding method which is suitable for the joining of similar and dissimilar UFG alloys of AA2024 and AA5083, which are mainly used in aerospace and aviation industries. Welding variables, such as pin profile, rotational speed, welding speed, and tilt angle were optimized using the Taguchi optimization technique. Different zones of UFSWed joints including stir zone (SZ), thermo-mechanically affected zone (TMAZ), and heat affected zone (HAZ) were investigated through OM, TEM, and SEM. The results showed that the tapered cylindrical pin, 1000 rpm rotational speed, 110 mm.min−1 welding speed, and 2.5° tilt angle were the optimal welding variables in terms of tensile strength. The microstructural results showed the formation of nano-size, recrystallized equiaxed grains with a size of 500 nm (the same size as that in the UFG base metal) in the optimal sample. The hardness in the weldment of the optimal UFSW sample decreased slightly, so that the efficiency of 85% was presented and the minimum hardness location (MHL) disappeared. The ultimate tensile strength (UTS) of 425 MPa and 64% efficiency were observed in the optimal conditions. Due to the presence of very fine grains and large dislocations, and the uniform distribution of precipitates in the underwater state, high strength and elongation were obtained.

Influence of Tool Pin Profiles on Aluminium Alloy A356 and Ceramic-Based Nanocomposites for Light Weight Structures by Friction Stir Processing

In this research, the main aim is to focus the enhancement of aluminium-based metal matrix composites for improving the attributes of light weight metals, aerospace structures and other tailor blank material properties. By this way, the friction stir processing (FSP) was the suited alternate technique to enhancing the mechanical attributes and superior microstructural amendment in the processed MMCs. Therefore, this study investigates the dispersion of ceramic-based strengthening particles of chromium oxide (Cr2O3) in the aluminium base matrix of A356 alloy. During the processing, the different tool pin sizes having the conical threaded tool pin profiles. Similarly, the tool spinning speed and tool travel speed also varied while in FSP. Before the processing, the A356 alloy was prepared by the grooved surfaces for packing the chromium oxide particles to compose the aluminium metal matrix composites. The tensile strength and hardness was employed to carry out from the friction stir processed A356 alloy with influencing of Cr2O3. The maximum occurred tensile processing parameters are 1500 rpm of spinning speed, 6 mm of tool pin sizes and 90 mm/min of tool travel speed. Similarly, the maximum obtained hardness processing parameter are 2000 rpm of spinning speed, 5 mm of tool pin sizes and 90 mm/min of tool travel speed. A scanning electron microscope was utilized to investigate the dispersed Cr2O3 in the A356 alloy for confirming the refinement grains in the nugget zones of FSPed A356 alloy. The increased grain boundary by the influence of different tool pin sizes was the major reason to produces the better mechanical properties in the processed A356/Cr2O3.

Comparative Analysis and Weld Behaviour of Mg-AZ31 and AL2024 with Various Profile Pin by Using FSW Process

Comparative Analysis and Weld Behaviour of Mg-AZ31 and AL2024 with Various Profile Pin by Using FSW Process

Correlation of microstructure, texture, and mechanical properties of friction stir welded Joints of AA7075-T6 plates using a flat tool pin profile

This study investigates the influence of square and hexagon tool pin profiles on the butt joint of AA7075-T6 plates through friction stir welding. In contrast to the AA7075-T6 base metal with a grain size of 32.736 μm, both square (4.43 μm) and hexagon (5.79 μm) pin profiles led to a significant reduction in grain size within the stir zone (SZ) of the weld cross-section. The SZ region exhibited a gradient in recrystallization and a notable fraction of high angle grain boundaries, attributed to continuous dynamic recrystallization influenced by variations in temperature and strain rate. Pole figure analysis revealed predominant shear texture elements (B/ B‾ and C) with minor A1*/A2* and A/ A‾, indicating elevated strains within the SZ. Orientation distribution function (ODF) analysis identified recrystallization texture elements such as Goss {110} <001>, cube {001} <101>, and P {011} <112>, along with shear texture components F {111} <112> and rotating cube (H) {001} <110>. Tensile and nanoindentation analyses demonstrated that the weld joint using a square-shaped pin profile exhibited higher strength, elongation, and elastic modulus compared to other weld joints. These findings suggest that the square tool pin geometry enhances material flow and grain refinement during welding, thereby improving the mechanical properties of the joint.

Experimental and optimization studies of friction stir processed Cu-TiB2 surface composites

The present study aims to fabricate different Copper surface composites (Cu-SCs) such as Copper-Silicon Carbide (Cu-SiC), Copper-Boron Carbide (Cu-B4C), Copper-Titanium Diboride (Cu-TiB2) with enhanced mechanical properties using friction stir processing. The Cu-SCs were fabricated at different levels of tool rotational speed (TRS), traverse speed (TS), and Vol. % of micro-sized Boron Carbide (B4C), Silicon Carbide (SiC), and Titanium Diboride (TiB2) reinforcements using blind hole method. The mechanical characteristics such as ultimate tensile strength (UTS), yield strength (YS), percentage of elongation (%EL), impact toughness (IT), and microhardness (H) of the Cu-SCs were evaluated and analyzed. In the next stage, the process parameters were optimized using a graph theory algorithm and utility concept and the TRS, and TS were 1120 rev/min, and 40 mm/min respectively. The Cu-SCs fabricated by using taper threaded cylindrical tool pin profile at four Vol.% of TiB2 possess enhanced the mechanical characteristics such as UTS, YS, % EL, IT, and H up to 282.07 MPa, 197.76 MPa, 12.96%, 16.67 J, and 168.6 HV. This was happened due to the increased recrystallization temperature, the pining effect, and restricting the grain boundary sliding. The microstructure in the stir zone of Cu-SCs fabricated with 4 Vol. % of SiC, 4 Vol. % of B4C, and 4 Vol. % of TiB2 particles exhibit fine grains. This is attributed to uniform distribution of the particles in the copper surface composites. The mechanical characteristics were also correlated with microstructures and fracture features.

Influence of pin profiles on temperature distribution, microstructure evolution and mechanical properties of friction stir welded AA6061

The friction stir welded (FSWed) butt-joints of 6061 aluminium alloy were fabricated by various pin geometries including cylindrical thread, tapered thread, triflate tapered thread and cylindrical non-thread. The attention was put on the role of the pin geometries in temperature distribution, microstructure evolution and mechanical properties of the joints. The history of changing welding temperature is validated through both experimental work and numerical simulation. The results showed that the highest welding temperature was obtained about 480 °C at triflate tapered thread pin in both experiment and numerical simulation. In all cases, the tensile strength was reached approximately 200 MPa with the joint efficiency of 80% in comparison with base metal. The fracture location of the joints was found in the heat affected zone, where the lowest value of hardness was obtained. The stress of root bend was lower than that of face bend. Crack-free on the welding surface of face bend indicated that the joints are ductile. However, the specific influence of pin geometries on the microstructure evolution and mechanical properties of the joints is insignificant in this work.