Dissimilar Aluminum Research Articles

Forgeability characterization of multi-material based functionally graded materials manufactured through friction stir consolidation

Solid state recycling allows direct recycling of metal chips into semi-finished products. This process category proved to lower the environmental impact of metals recycling. Friction stir consolidation (FSC) is a new solid-state technique taking advantage of friction heat generation and severe plastic deformation to consolidate chips into billets. The new frontier of FSC process could be its evolution from recycling techniques towards the concept of upcycling technique: reuse (discarded objects or material) in such a way as to create a product of higher quality or value than the original. The authors have recently successfully applied FSC for producing multi-material based functionally graded materials (FGM). In this paper, the forgeability of the billet consolidated out of two dissimilar aluminium alloys AA 7075 and AA 2011-T3 chips, was analyzed. A proper forging test was designed, and mechanical and metallurgical properties of the forged parts were assessed through Vickers hardness measurements.

Microstructural and Mechanical Properties of Dissimilar Aluminium Alloys by Friction Stir Welding

In the present study, the dissimilar aluminium alloys AA 2014-T651 and AA 7075-T651 of 16 joints was successfully joined with (four welding speeds (50, 60, 70, 80 mm/min), four rotational speeds (900, 1000, 1100, 1200 rpm), four different weld tool profiles (T1=12/4, T2=15/5, T3=16/4, T4=20/5 in D/d ratio) by friction stir welding machine. In the optical microstructure and SEM very fine equiaxed grains are formed in the stir zone. The maximum hardness value is 150 HV obtained in the weld nugget area of the specimen 2 under the conditions of 900 rpm, 70 mm/min for T3 profile. Compare to other tool profiles T3 profile attained maximum hardness value. The minimum hardness value is attained for the specimen 13 for the tool profile T1 was 103 HV compared to all tool profiles. In post weld heat treatment conditions, hardness values were decreased compare with as weld conditions due to over heating followed by ageing. The maximum joint efficiency attained is around 90 to 95% with T2 and T3 profiles at rotational speed of 1000 rpm, 1200 rpm and welding speed of 60, 70 mm/min. The T1 profile attained least joint efficiency of 69.5 % at 900 rpm, 50 mm/min, since it has very less shoulder diameter or contact area and maintain a D/d ratio is 3.

Influence of Friction Stir Processing on the Mechanical and Microstructure Characterization of Single and Double V-Groove Tungsten Inert Gas Welded Dissimilar Aluminum Joints

Influence of Friction Stir Processing on the Mechanical and Microstructure Characterization of Single and Double V-Groove Tungsten Inert Gas Welded Dissimilar Aluminum Joints

Effect of double-side welding on the microstructural characteristics and mechanical performance of dissimilar AA6061-AA5052 aluminium alloys

In this study, cold metal transfer (CMT) based double-side welding process was employed to weld AA5052-H32 and AA6061-T6 plates having a thickness of 6 mm. The microstructure and mechanical integrity of the weldment was examined systematically. Symmetric and defect free joint with full penetration was achieved. The multiple heating and cooling cycles during CMT welding did not affect the weldment while the microstructure comprised of columnar and equiaxed dendrites and the heat affected zone (HAZ) width was < 50 µm at all interfaces. Precipitates such as Al3Mg2, Mg2Si, and α-Al(FeMn)Si were observed in the fusion zone. Intergranular Al-Si eutectic structure along with few microliquefaction cracks were noticed in the α-Al matrix. The maximum tensile properties for double-side welded joint were 214 MPa and 12.30 % with a joint efficiency of 70.68 %. Tensile specimens underwent ductile fracture in the weaker AA5052-H32 side with confined plastic deformation.

Role of traversing speed and axial load on the properties of friction stir welded dissimilar AA6101-T6 AND AA1350 aluminium alloys

ABSTRACT Traditionally, AA6101-T6 and AA1350 aluminum alloys find prominent place in many industrial applications like electrical bus bar utilities for the sake of better conductivity. Friction Stir Welding is a non-traditional solid-state welding technique that was invented and developed by The Welding Institute. In this analysis, AA6101-T6 and AA1350 alloys have been put on experimentation with friction stir welding by varying axial load (5 kN to 9 kN) and traversing speed (60 mm/min to 120 mm/min). In order to examine the weld quality, properties such as tensile, wear and microstructural analyses have been carried out. From the results, it was observed that the weldment made with 7 kN axial load and 90 mm/min traversing speed exhibited better joint properties. Similarly, the weldment made with 5 kN axial load and 120 mm/min traversing speed exhibited poor joint properties. This has been attained due to the variations in heat input, metals softening and grain coarsening at weld nugget. Taguchi L9 orthogonal array with ANOVA and Signal to Noise ratio have been adopted to understand the contribution of axial load and traversing speed on the properties of weldments. Results reveal that traversing speed is statistically significant on the properties of weldment, when compared to axial load.

Mechanical properties optimization and microstructures of diffusion bonded AA2014/AA7075 al alloys

Diffusion bonding has been successfully used to join dissimilar high-strength aluminium alloys. In bonding AA2014 with AA7075 aluminium alloy, the main diffusion bonding process parameters were optimized to achieve optimum shear and ram tensile strengths. For the strategical planning of experiments, the design of experiment concept was used, as well as the response surface methodology to create statistical models for optimizing the process parameters. The bond strength improved as the interface thickness increased, but above 6 µm (at about 375 °C), the bond strength began to deteriorate. Similarly, the stiffness of the joint interface increased as the process temperature increased due to the development of interfacial phases. The empirical findings were evaluated, and the optimal bonding range was determined in order to maximize the bond’s shear and ram tensile strength.

Microstructure and strain hardening behaviour at the inter-mixing zone of water-cooled friction stir welded dissimilar aluminum alloys

• The strain hardening behaviour at the inter-mixing zone of FSW was investigated. • Strain hardening behaviour was correlated with grain size, grain boundary wetting and texture. • The WCFSW joint resulted in higher tensile strength and strain hardening rate. The present study investigated the effect of water-cooling friction stir welding (WCFSW) on microstructure characteristics and strain hardening behaviour along the intermixing zone or stir zone of dissimilar 5083-6061 aluminum alloys. Results indicated that WCFSW had refined grain structure, high dislocation density and finer intermetallic compound formation due to intense plastic deformation at the stir zone. Textures components such as Brass [{1 1 0} 〈1 1 2〉] and Goss [{1 1 0} 〈0 0 1〉] were predominantly evolved in FSW samples. The tensile strength and strain hardening rate were maximum in the WCFSW joint attributed to finer grains, higher dislocation density and texture evolved.

Friction Stir Welding of Different Aluminum-Silicon Alloy Compositions Utilizing Conventional Vertical Milling Machine

Friction-Stir Welding (FSW) is a solid-state procedure for welding two plates in which there is relative motion between the tool and workpiece, which creates the heat required for the material of the two edges to join by atomic diffusion. The present research article focuses on friction stir welding of dissimilar aluminum-silicon alloys utilizing a vertical milling machine and altering process parameters. Moreover, testing is done on the weld joints for the best process parameter. The process parameters considered in the present work for joining dissimilar aluminum alloys primarily were a constant tool feed rate of 63 mm/min and three varied tool rotational speed rates of 710, 1000 and 1400 rpm. Mechanical characterization of weld joints, such as tensile, hardness, microstructural studies and surface roughness tests, were used to identify the most optimal parameter. The results indicated that Al-Si alloys having Al-5%Si with Al-12%Si FSW joints welded using 1000 rpm tool rotational speed proved to have better hardness and lesser surface roughness while, Al-Si alloys having Al-12%Si with Al-17%Si FSW joints, had better hardness and roughness properties when welded using 1400 rpm tool rotational speed. Concerning the ultimate tensile strength, Al-Si alloys having Al-5%Si with Al-12%Si and Al-12%Si with Al-17%Si FSW joints welded using 1400 rpm tool rotational speed offered better results.

Effect of Welding Parameters and Tool pin features on Mechanical Properties of Dissimilar Aluminum Alloy Friction Stir Welds

ABSTRACT The present work describes the effect of welding parameters and tool pin features during friction stir welding of dissimilar AA6082 and AA7050. Mechanical behaviour of dissimilar joints fabricated by using two distinct tool pin features, welding speed (WS), and rotary speed (RS) were compared for superior weld properties. All joints fabricated from tool having threaded cylindrical (TC) pin feature were defect-free, whereas welds fabricated by the plain cylindrical (PC) pin tool at 800 rpm RS using different WS were found defective. At the same RS and WS parameters combinations, the width of the softened region was found comparatively less in PC tool welds. The highest ultimate tensile strength (UTS) and elongation of 187.33 MPa and 7.55% were obtained for weld fabricated from TC tool at 180 mm.min−1 WS and 800 rpm RS. However, the highest yield strength (YS) value of 168.8 MPa was obtained for dissimilar joints produced using the PC tool at 180 mm.min−1 WS and 1600 rpm RS. The tensile specimens of defect-free dissimilar joints were fractured from respective minimum hardness locations in ductile mode.

Enhancing the joint of dissimilar aluminum alloys through MIG welding approach assisted by ultrasonic frequency pulse

In this work, AlSi10MgMn die cast aluminum alloy and 6061 aluminum alloys were bonded using Metal inert gas (MIG) welding assisted by ultrasonic frequency pulse (UFP). The effect of UFP on the weld shape, joint porosity, microstructure and mechanical properties of the joints was investigated. Results revealed a distinct decrease in joint hydrogen porosity defects and pore size via the UFP-MIG welding approach in comparison to a directly bonded joint. This method resulted in the tensile strength of the joint reaching 185% of the joint bonded without UFP. The regulating mechanism of UFP on the joint porosity was determined.

Effects of semi-solid structure on interface formation of dissimilar aluminum to galvanized steel welds produced by load-controlled Refill Friction Stir Spot Welding

Refill Friction Stir Spot Welding (Refill FSSW) allows welding dissimilar materials providing excellent bonding between both parts. On this work, a multi-scale analysis of load-controlled Refill FSSW was performed to analyze dissimilar AA6016-T4 and Zn-coated DX56D steel joints. These were produced using optimized process parameters and analyzed in both as-welded and bake-hardened conditions. During the process, fusion and subsequent dispersion of Zn favored the formation of a semi-solid structure characterized by an intense microsegregation. Therefore, incipient melting of Zn-rich phase followed by eutectic reaction was observed. The presence of liquid phases along the grain boundaries led to a complex relationship between mechanical properties, microstructure and processing variables. Joints with enhanced mechanical properties were produced by limiting the growth of intermetallic compounds (IMC) at the interface, which coupled with stir zone (SZ) strengthening due to Zn dispersion, led to less pronounceable secondary bending effects. The bake hardening process was also found to have a substantial influence on diffusion-dependent mechanisms and, consequently, on the final performance of the welded joint. The results highlighted a great potential of load-controlled Refill FSSW for producing high-strength dissimilar joints in short cycles, which is desirable for applications in the automotive industry.

Wire and arc additive manufacturing of dissimilar 2319 and 5B06 aluminum alloys

• Fracture occurred at a layer thickness above the interface layer during tensile test, regardless of the deposition order of the dissimilar alloys. • Thermal stress due to long dwell time and the remelting of S-Al 2 CuMg phase are the main factors promoting crack initiation. • Cracks mainly propagate along the aggregated pores and strip θ-Al 2 Cu phase distributed along the grain boundary. • The component deposited with bottom half of 2319 and top half of 5B06 exhibits better mechanical properties, which are approaching to that of 2319 base metal. Aluminum alloy is the most widely used light alloy at present. By combining different types of aluminum alloys, their functional properties can be expanded. In the present research, two components composed of 2319 (Al-6.5Cu) and 5B06 (Al-6.4Mg) dissimilar alloys were fabricated by wire and arc additive manufacturing (WAAM). The deposited component with the bottom half of 2319 and the top half of 5B06 exhibits better mechanical properties than its counterpart deposited vice versa. Its ultimate tensile strength, yield strength, and elongation are 258.5 MPa, 139.3 MPa, and 5.6%, respectively, which are only slightly inferior to the mechanical properties of 2319 base metal. The results show that for both components, fracture occurred at a layer thickness above the interface layer during the tensile test, regardless of the deposition order. It appears that the thermal stress due to the long dwell time and the remelting of the S-Al 2 CuMg phase are the main factors promoting crack initiation. Depending on the deposition order, cracks propagate either along the aggregated pores or strip θ-Al 2 Cu phase distributed along the grain boundary. By analyzing the heat input and selecting the appropriate depositing order, the strength of WAAM dissimilar aluminum alloys can be effectively improved through the proper control of microstructure and internal defects.

Fatigue Behavior of a Dissimilar Aluminum Alloy Welding Joint With and Without Natural Defect

Fatigue Behavior of a Dissimilar Aluminum Alloy Welding Joint With and Without Natural Defect

A Comparative Study of Self-Piercing Riveting and Friction Self-Piercing Riveting of Cast Aluminum Alloy Al–Si7Mg

Abstract Cast aluminum alloys are promising materials that can simplify the manufacturing process of automobile body structures. However, the low ductility of cast aluminum poses significant challenges to existing riveting technologies. In the present work, dissimilar AA6061-T6 aluminum alloy and Al–Si7Mg cast aluminum were joined by self-piercing riveting (SPR) and friction self-piercing riveting (F-SPR) processes to reveal the effect of friction heat on rivetability of low-ductility cast aluminum alloys. The joint macro-morphology, microstructure, peak tooling force, microhardness distribution, tensile-shear, and cross-tension performance of the two processes were comparatively studied. Results indicated that the in-situ softening effect of friction heat in the F-SPR process could effectively improve the ductility of cast aluminum, avoid cracking, and reduce the tooling force by 53%, compared to the SPR process. The severe plastic deformation and friction heat induced by rivet rotation results in refined equiaxed grains of aluminum near the rivets and solid-state bonding between aluminum sheets in the rivet cavity. The F-SPR joints are superior to SPR joints in both tensile-shear and cross-tension performance due to the avoidance of cracking, increase of mechanical interlocking, and solid-state bonding of interfaces. Significantly, when Al–Si7Mg is placed on the lower layer, the peak tensile-shear and cross-tension loads of the F-SPR joints are 7.2% and 45.5% higher than the corresponding SPR joints, respectively.

Improvement of Mechanical Behavior of FSW Dissimilar Aluminum Alloys by Postweld Heat Treatments

AA6262 and AA5456 alloys are welded through friction stir weld (FSW) with process parameters of tool speed of 1200 rpm, welding speed of 25 mm/min, and tool angle of 3 degree. A cylindrical shape HSS-13 tool is used to perform the welding process To improve mechanical properties of tensile strength (TS), yield strength (YS), elongation%, hardness, and wear behavior, postweld heat treatment was conducted on the FSW sample at different temperatures from 300°C to 500°C. The influence of heat treatment (HT) changes the material characteristics. It is observed that the maximum TS (209 MPa) and YS (178 MPa) are identified when maintaining temperature 350°C on the FSW sample. The reduction in elongation of as-welded joints is entirely improved by HT, and the elongation percentage is almost increased to 5% when increasing temperature on the heat treatment process, and hardness test results exhibited that the increased hardness value (120Hv) is found at HT-300°C nugget zone distance of 0 to 5 mm range.

Mechanical Properties Enhancement of Dissimilar AA6061-T6 and AA7075-T651 Friction Stir Welds Coupled with Deep Rolling Process.

The main purpose of this research was to enhance the mechanical properties of friction stir welds (FSW) in the dissimilar aluminum alloys 6061-T6 and 7075-T651. The welded workpiece has tensile residual stress due to the influence of the thermal conductivity of dissimilar materials, resulting in crack initiation and less fatigue strength. The experiment started from the FSW process using the 2k full factorial with the response surface methodology (RSM) and central composite design (CCD) to investigate three factors. The experiment found that the optimal rotation speed and feed rate values were 979 and 65 mm/min, respectively. Then, the post-weld heat treatment process (PWHT) was applied. Following this, the 2k full factorial was used to investigate four factors involved in the deep rolling process (DR). The experiment found that the optimal deep rolling pressure and deep rolling offset values were 300 bar and 0.2 mm, respectively. Moreover, mechanical property testing was performed with a sequence of four design types of workpieces: FSW, FSW-PWHT, FSW-DR, and FSW-PWHT-DR. It was found that the FSW-PWHT-DR workpiece had an increase in tensile strength of up to 26.29% and increase in fatigue life of up to 129.47% when compared with the FSW workpieces, as well as a maximum compressive residual stress of −414 MPa.

Effect of tool pin shapes on microstructure and mechanical behaviour of friction stir welding of dissimilar aluminium alloys

The mechanical and microstructure characterizations of friction stir welding (FSW) joints of 5052-H32 with 6061-T6 aluminium alloys (AA) were investigated in this research. With two distinct tools (Taper cylinder and Threaded cylinder), the microstructural change associated to the mechanical characteristics of an FSW of dissimilar AA has been investigated under constant welding conditions such as welding speed (WS) and tool rotation speed (TRS) are 60 mm/min and 900 rpm respectively. For instance, in the hardness profile, the lesser values were obtained in the AA6061 alloy. The maximum and minimum weld joint strength were approximately 165.84 MPa and 133.85 MPa from the FSW, showed lower strength than the base material. The highest joint Efficiency of the dissimilar weld was 78.37 %, and the maximum hardness is 71 HV obtained. The defect-free stir zone development and grain size strengthening were credited with it as well. The elongations of the welded joints were measured to be 11.6 % and 7.2 %. It was discovered that using a tool with a taper pin profile and a threaded pin profile produced a joint with better tensile strength, a larger nugget area, and a smoother surface finish. Finally, it was discovered that a fine grain microstructure created by using a taper pin profile resulted in stronger welded connections compared with threaded pin profile.

Research on the joining of dissimilar aluminum alloys by a dieless clinching process

Research on the joining of dissimilar aluminum alloys by a dieless clinching process

Prediction of Filler Added Friction Stir Welding Parameters for Improving Corrosion Resistance of Dissimilar Aluminium Alloys 5052 and 6082 Joints

Abstract The aluminium alloys 5052 and 6082 are extensively used in manufacturing lighter structural members, having improved strength and resistance to corrosion. Magnesium (Mg) and Chromium (Cr) powder were the filler materials selected for enhanced corrosion protection properties in this investigation. Friction stir welding (FSW) process parameters viz., spindle speed, welding speed, shoulder penetration, the centre distance between the holes and filler ratio are used to forecast the minimum corrosion rate from different weld regions of AA5052-AA6082 dissimilar joints. Response surface methodology based on a central composite design was used to evolve the mathematical models and estimate dissimilar FSW joints’ corrosion rates. Response optimization shows that the minimum corrosion rate was achieved by the welding parameters of spindle speed 1000 rev/min, welding speed 125 mm/min, holes spacing of 2 mm and filler ratio 95% of Mg and 5% of Cr.

Comparison of the Influence of Temperature Change Distribution of Three Surface Regions on the Hardness of Two Dissimilar Aluminum Alloys Welded by Friction Stir Welding

Aluminum is one of the most commonly used alloys in industrial applications due to its significant qualities such as resistance to wear, high hardness resistance, and high conductivity. This study will concentrate on the hardness resistance of two dissimilar aluminum alloys at different rotational and travel velocities, where the behavior of the alloys' hardness resistance will be studied after the welding process, from the welding center to the alloys' edges, and this will be done in three areas. Due to temperature changes at the weld in these three separate regions, the first area was at the start of the welding process, the second in the midst of the model, and the third area was at the conclusion of the welding process, to examine the influence of temperature on the hardness resistance. The results showed that increasing the travel velocity of the feed cart and keeping the rotational velocity constant increased the hardness resistance, whereas increasing the rotary tool velocity and keeping the travel velocity of the feeding cart constant decreased the hardness resistance of the two welded alloys. The maximum hardness resistance recorded in the model's welding center (3-3) and its value were more than (49.47 percent) the lowest hardness resistance recorded for all models, which was for the model (7-1).