Friction Stir Welding Of Aluminum Research Articles

Effect of Pin Length and Compression Force in Double Side Friction Stir Welding on Tensile Strength of AA1100

Friction Stir Welding (FSW) is solid state welding without additives and does not produce pollution. There are two FSW welding methods, namely single side (FSW) and double side (DFSW). The FSW process in previous studies using aluminum materials, especially AA 1100 type, has not obtained optimum joint strength. Therefore, it is necessary to conduct a research study on improving the quality of tensile strength of welding results using the DFSW method on AA1100. The purpose of this study is to determine the effect of variations in pin length and compressive force on the maximum tensile strength of the results of Double Side Friction Stir Welding Aluminum Alloy 1100 welding joints. The method used in this research is experimental. The welding process uses Double Side Friction Stir Welding, by varying two independent variables namely pin length 1.5 mm, 2 mm, 2.5 mm and compressive force 30 kg, 35 kg, 40 kg, 45 kg. The controlled variables used include travel speed (10 mm/min), heating temperature (250℃), shoulder diameter (25 mm), heating plate width (10 mm), and Aluminum AA1100 plate thickness (3.5 mm), with butt joint type welding. The data analysis used is Factorial Design of Experiment (DOE). The results of this study indicate that pin length and compressive force affect the tensile strength of AA1100 material welds. The maximum tensile strength value of DFSW welding results is 90.16 MPa or 80.5% of the tensile strength of the parent material. The maximum tensile strength value was obtained from the interaction of 2 mm pin length and 45 kg compressive force.

Numerical simulation of bidirectional fluid-solid coupling in friction stir welding of aluminium and magnesium dissimilar alloys

Abstract During friction stir welding, the flow degree of metal materials and the welding temperature determine the microstructure and mechanical properties of the joint. This paper establishes a bidirectional fluid-solid coupling model for dissimilar friction stir welding of aluminum and magnesium alloys. Combining simulation results and experimental research, it quantitatively analyzes the distribution laws of the flow field, temperature field, and stress field during the welding process. The results show that in terms of temperature field distribution, the simulated temperature matches the thermal cycle curve of the measured temperature, with the welding temperature peak located in the rear area of the shoulder’s bottom. In addition, the temperature field on both sides of the weld is asymmetrically distributed, with the temperature on the aluminum side being higher than that on the magnesium side. In terms of flow field distribution, the material flowability decreases as the distance from the stirring head increases. Therefore, the material flow patterns around the stirring head and in areas farther from the stirring head are different. It was also found that the best material flow was at the bottom of the shoulder and the material flow rate was higher on the magnesium side than on the aluminium side. It is noteworthy that under the combined action of the stirring pin and the shoulder, the material mixing zone and the magnesium alloy shift towards the aluminum side. In terms of stress field distribution, the equivalent stress of the stirring head is distributed differently on the aluminum side and the magnesium side.

Revealing microstructure evolution and mechanical properties of Al/Cu joints during high-speed friction stir welding

Friction stir welding provides several advantages, including relatively low welding temperature, no thermal crack, and excellent joint performance. However, due to the narrow process window, the research on the friction stir welding of aluminum and copper is mainly focused on the lower welding speed range, which greatly affects the welding efficiency. Addressing the challenge of increasing welding speed and optimizing process parameters has become an urgent priority. In addition, the dynamic recrystallization behavior during high-speed Al–Cu friction stir welding is complex, and the microstructure evolution is still unclear. In order to clarify these issues, the high-speed friction stir welding (HSFSW) experiment was carried out, and the influence of rotation speeds on microstructure evolution and mechanical properties of joints at high welding speed was investigated. The results show that when welding speed is fixed at 400 mm/min and rotational speeds are in the range of 2000∼2500r/min, the joints can be obtained with good surface morphology and no internal defects. The ultimate tensile strength of specimen is 191 MPa at the process parameters of 2250r/min-400 mm/min, which is 77% of the strength of copper base material. As the rotation speed increases, a thick intermetallic compounds layer appears inside the joint. Due to the influence of thermal cycle and stirring of pin, the nugget zone undergoes a large amount of recrystallization behaviors and forms fine equiaxed grains, which is conducive to refined crystalline strengthening, thus improving mechanical properties of joints.

Effect of variations in tool offset friction stir welding aluminum 5083 on tensile strength and hardness

Effect of variations in tool offset friction stir welding aluminum 5083 on tensile strength and hardness

Experimental study on high-precision measurement of surface temperature in friction stir welding aluminium alloy 2219 based on infrared thermometry

In friction stir welding (FSW) of aluminium alloy 2219, the welding temperature critically influences the weld quality. Accurate measurement of the welding temperature is essential for effective welding process control. However, the conventional approach of non-contact infrared thermometry faces significant challenges in FSW due to the inherently low and variable emissivity of aluminium alloys, making it susceptible to environmental radiation interference. This paper proposes a novel, high-precision method for measuring the surface temperature of FSW aluminium alloy 2219 based on infrared thermometry principles. Initially, the study delves into these principles, analysing factors that affect the accuracy of infrared thermometry in the context of FSW in industrial settings. To enhance the surface emissivity of the weldments, a high-emissivity coating is applied to the aluminium alloy surface. Additionally, strategic adjustments in the positioning of the thermal imager and careful selection of the measuring area effectively mitigate interference from the FSW tool’s radiation. Conventional methods report a temperature measurement error greater than 2%, while the proposed method reduces this error to 1.2%. The effectiveness and practical utility of the method are validated through FSW experiments on flat plates and rocket tank rings, corroborated by comparative analyses with surface thermocouple temperature measurements. This confirms the viability of the proposed method for high-precision temperature measurement in aluminium alloy FSW applications.

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.

КОМПЬЮТЕРНОЕ МОДЕЛИРОВАНИЕ ТЕМПЕРАТУРНЫХ ПОЛЕЙ В СВАРНОМ ШВЕ ПРИ ИЗМЕНЕНИИ ТЕХНОЛОГИЧЕСКИХ ПАРАМЕТРОВ СВАРКИ ТРЕНИЕМ С ПЕРЕМЕШИВАНИЕМ АЛЮМИНИЯ И МЕДИ

This paper discusses numerical modeling of temperature fields in friction stir welding (FSW) of aluminum (AD1) and copper (M1). A three-dimensional thermomechanical finite element model based on the coupled Euler-Lagrange (CEL) approach is used. The paper models and experimentally confirms the influence of FSW parameters on the distribution and peak temperature values in weld zones. The maximum temperature values are observed on the copper side. This is due to the high thermophysical properties of copper compared to aluminum. Changing the rotation speed of the welding tool from 800 rpm to 1000 rpm leads to an increase in the peak temperature from 492 °C (800 rpm) to 692 °C on the side of the copper plate (1000 rpm). The maximum discrepancy between the calculated and experimental temperature curves does not exceed 9%, which is quite acceptable for assessing the temperature field.

Residual stress tests and predictive model of friction stir welded normal-strength aluminium alloy H-shaped sections

To address the challenges of difficult extrusion for super-large cross-section aluminium alloy members, pairs of T-shaped sections were proposed to be longitudinally friction stir welded (FSW) to form the H-shaped sections widely used in structural engineering. It was significantly different from the previous member forming method that one web plate and two flange plates were welded at the flange-web junctions. To understand the novel FSW-induced residual stress distributions and magnitudes in the H-shaped sections, six specimens made of 6061-T6 and 6013-T6 normal-strength aluminium alloys, including various width-to-thickness ratio and plate thickness, were tested using the sectioning method, leading to over 4000 original readings of compressive and tensile residual stresses. The analysis results showed that great tensile residual stresses were clearly concentrated within the web weld, and then rapidly descended to lower compressive stresses near the weld region, followed by approximately linear regression to zero state from the weld edge to the flange-web junction, while the flange data points were relatively scattered. The compressive and tensile residual stresses in each flange and web plate were observed to be slightly associated with the width-to-thickness ratio and plate thickness. A simplified multi-linear residual stress distribution model, including the magnitudes and ranges of constant and linear variation curves, was proposed for the FSW aluminium alloy H-shaped sections, and good accuracy and consistency were observed between the test and predicted results.

Investigation of Microstructural and Mechanical Characteristics of Friction Stir Welded Aluminum Alloy 7075-t6

Investigation of Microstructural and Mechanical Characteristics of Friction Stir Welded Aluminum Alloy 7075-t6

Insight into the tribocorrosion of AA7050 friction stir welding joint

Friction stir welding (FSW) induces significant microstructural modifications in AA7050, involving the dynamic recrystallization in the weld nugget zone (WNZ) and coarsening of intermetallic particles (IMPs) in the heat-affected zone (HAZ). Accounting for the enhanced Volta potential and nano-hardness, the coarse IMPs in HAZ contribute to anodic attack and initiation of wear cracks, thereby facilitating tribocorrosion damage. The multiple galvanic corrosion represented by nano-precipitate MgZn2 vs. Al-matrix, coupled with the absence of the ball-bearing effect originated from IMPs, contribute to the inferior tribocorrosion performance of WNZ. This research offers valuable references into the tribocorrosion mechanism of FSW aluminium alloy joints.

Mechanical properties of base metal and heat-affected zone in friction-stir-welded AA6061-T6 at ultra-low temperature of 20 K

This study investigates the mechanical properties of a friction-stir-welded (FSW) AA6061-T6 aluminum alloy at ultra-low temperature (ULT) of 20 K. In-situ neutron diffraction and orientation imaging microscopy were employed to compare the tensile deformation behavior of the base metal (BM) and heat-affected zone (HAZ) in the FSW aluminum plate. The results demonstrate that compared to room-temperature (RT), ULT induces a significant improvement in tensile strength and ductility in both the BM and HAZ. The enhanced mechanical properties in BM at ULT result from a more homogeneous deformation than occurs at RT. On the other hand, HAZ at ULT exhibits an even lower yield strength than at RT, but the strain hardening rate (SHR) is the most significant among the alloys, leading to a tensile strength of 346 MPa and the highest ductility of 46.8%. The lowest yield strength corresponds to the lowest-hardness zones in HAZ, caused by dissolved/coarsened precipitates during the FSW process. The highest SHR in HAZ at ULT is attributed to the hardening of the {111} grain families and finer dislocation cell structures. The dislocation densities of both the BM and HAZ increased considerably during tensile deformation at ULT, which accounts for the improvement in tensile strength. Revealing the mechanism behind the remarkable improvement in the mechanical properties of FSW AA6061-T6 at ULT suggests its applicability for cryogenic applications.

Relationship between mechanical behavior and process factors in friction stir welding aluminum alloys

The friction stir welding (FSW) procedure is the main topic of this research study among the various welding techniques. The study focuses on the interaction between the mechanical properties of 3003 aluminum alloy and the process parameters (rotation speed, welding speed, and dwell time) in the form of rolled plates of 2 mm thickness, end-to-end and welded at 90° and 45°. The welds were made by varying the speed of rotation (1000, 2000 rpm) and setting the tool feed at 500 mm/min. This experimental approach is also based on varying the tilt of the welding tool from 0° to 2°. It has been shown that the studied parameters play an important role in the characterization and optimization of the above mentioned weld joints. Therefore, and based on the results obtained, the use of the 90° joint remains the best in terms of strength.

Advancements in Friction Stir Welding Techniques for Enhanced Performance in Aluminum Alloy Structures

Abstract: Friction Stir Welding (FSW) is a solid- state welding method that can be utilized on both comparable and dissimilar materials. The technology is frequently utilized because it generates quality welds and avoids common issues like solidification and liquefaction cracks that are connected with fusion welding processes. The FSW of Aluminum 5086 andits alloys has been commercialized, and there is renewed interest in connecting dissimilar materials. However, before the process can be commercialized, research studies must be conducted to describe and set process windows. In particular, FSW has prompted researchers to try combining incompatible materials with different characteristics, such as Aluminum 5086, and sound welds with no or few intermetallic compounds have been formed.

Modeling and Simulation of Friction Stir Welding of Aluminum and Magnesium Alloys Using Finite Element Analysis

Modeling and Simulation of Friction Stir Welding of Aluminum and Magnesium Alloys Using Finite Element Analysis

Experimental study on mechanical behaviour of friction stir welded aluminium alloy butt joints

The purpose of this paper is to understand the softening extent and stress-strain behavior of the normal-strength 6061-T6, 6013-T6, and high-strength 7075-T6 aluminium alloy butt joints using the novel friction stir welding (FSW) technique. A total of 107 monotonic tensile coupons and 33 Vickers hardness coupons were prepared from 8- or 12-mm thick welded plates using various tool rotation speed, welding transverse speed and tool configurations. The surface morphology, stress-strain curves and hardness distribution laws after welding were evaluated. The W-shaped hardness profiles were clearly observed, with the fracture location positively correlated at the lowest point of Vickers hardness near the edge of the weld toe. The strength reduction and softening extent of extruded aluminium alloys in T6 temper induced by FSW were superior to those of aluminium alloys using fusing welding process outlined in the Chinese and European standards, indicating the effectiveness and applicability of the FSW technique in the formation of components and connections for aluminium alloy structures. Additionally, the current widely used constitutive models generally yielded under-estimations on the strength under large strains. The developed three-stage Ramberg-Osgood model, using seven key input parameters, significantly improved the accuracy and consistent predictions in the full-range stress-strain curve of FSW aluminium alloys. Furthermore, the suggested model could still achieve a great balance between accuracy and practicality when using just three common available parameters with the employment of predictive expressions on other four parameters.

Optimizing the Mechanical Properties of the Weld in the Friction Stir Welding of Aluminum and Magnesium (A365–AZ91C)

The friction stir welding of A365 and AZ91C alloys was conducted in this study to assess the effect of tilt angle, linear velocity and rotating speed on the elongation, hardness and tensile strength using the response surface method. Then, the weld microstructure was investigated by SEM, TEM and EDS analysis to deeply investigate the structure of A365–AZ91C weld. It was realized that the grain size of weld joint has grown and the crack and tunnel were formed when the rotating speed improved from 1000 to 2000[Formula: see text]rpm, which produced a decline in the hardness and strength and a rise in the elongation. Moreover, an increment of linear velocity up to 60[Formula: see text]mm/min led to the refinement of the weld microstructure, which was followed by an enhancement in the strength and hardness of the weld, whereas the elongation deteriorated. In the case of tilt angle, the highest elongation and strength were detected at a tilt angle of 2∘, but the highest hardness was observed at a tilt angle of 4∘ because of the nucleation of Al3Mg2 and Al[Formula: see text]Mg[Formula: see text] intermetallics. Results of optimization exhibited that the concurrent improvement of the strength, hardness and elongation can be acquired with the tilt angle of 3∘, rotating speed of 1600[Formula: see text]rpm and linear velocity of 53[Formula: see text]mm/min.

Investigation of Tool Degradation during Friction Stir Welding of Hybrid Aluminum-Steel Sheets in a Combined Butt and Overlap Joint.

Friction stir welding, as a solid-state welding technique, is especially suitable for effectively joining high-strength aluminum alloys, as well as for multi-material welds. This research investigates the friction stir welding of thin aluminum and steel sheets, an essential process in the production of hybrid tailor-welded blanks employed in deep drawing applications. Despite its proven advantages, the welding process exhibits variable outcomes concerning formability and joint strength when utilizing an H13 welding tool. To better understand these inconsistencies, multiple welds were performed in this study, joining 1 mm thick steel to 2 mm thick aluminum sheets, with a cumulative length of 7.65 m. The accumulation of material on the welding tool was documented through 3D scanning and weighing. The integrity of the resulting weld seam was analyzed through metallographic sections and X-ray imaging. It was found that the adhering material built up continuously around the tool pin over several welds totaling between 1.5 m and 2.5 m before ultimately detaching. This accretion of material notably affected the welding process, resulting in increased intermixing of steel particles within the aluminum matrix. This research provides detailed insights into the dynamics of friction stir welding in multi-material welds, particularly in the context of tool material interaction and its impact on weld quality.

搅拌针偏移量影响铝镁异质金属搅拌摩擦焊材料流动的数值模拟

搅拌针偏移量影响铝镁异质金属搅拌摩擦焊材料流动的数值模拟

A Novel Procedure for Friction Stir Welding Aluminium to Copper by Using an Aluminium Run-On Plate

Conventional friction stir welding of aluminium to copper often results in the formation of deleterious intermetallic compounds. In order to overcome this concern, an innovative procedure consisting of using an aluminium run-on plate is presented. Long continuous aluminium-copper welds, without any defect, were obtained by this procedure. The run-on plate inhibits the formation of intermetallic compounds around the pin by allowing the use of high tool offset, without the formation of discontinuities at the interface. The generation of an aluminium volume around the tool, which detaches very small copper particles from the copper plate, gives rise to stir zones composed of a uniform distribution of copper particles in an aluminium matrix and with a minimal formation of intermetallic compounds. Comparing to the conventional welds, a significant improvement in the mechanical strength was achieved by welding with this non-conventional procedure.

Mechanical Properties of Welded by Friction Stir Welding Aluminium Alloy AA 5754

Friction stir welding is one of the most original methods for welding devised in recent years. As this welding method possesses advantages compared to conventional fusing welding methods, scientific research on its features and improvement is increasing. The advances in the knowledge of the process of friction stir welding allow its increasing application in different areas, such as aircraft and automotive industries, railway transport, nuclear industries etc. During friction stir welding the joined parts are in a solid state. This welding method is mainly used for joining aluminium and its alloys.The stirring and mixing of the material and the temperature during friction stir welding are the main factors that determine the possibility of obtaining weldments with precise mechanical properties.The present study aims to research the influence of the pin`s configuration on different quality aspects of the weldments at chosen parameters of the welding mode. To achieve this, pins with different geometry and coatings were used. Results that demonstrate the influence of the pin`s geometry and the process parameters on the temperature, structure, and mechanical properties of joined by friction stir welding weldments of aluminium alloy AA 5754 4 mm thick are presented. The influence of the pin`s geometry on defect formation during welding was determined.