Dissimilar Material Joints Research Articles

On formation of Al[sbnd]O[sbnd]C bonds at aluminum/polyamide joint interface

Strong dissimilar materials joints consisting of aluminum alloy and polyamide 66 (PA66) plates were produced by a new joining method: friction lap welding (FLW). To understand the key joining mechanism, special samples were made by evaporation of aluminum oxide onto PA66 plates to form an aluminum alloy/PA66 interface. X-ray photoelectron spectroscopy (XPS) was used for characterizing the resulting interfacial chemistry in these aluminum alloy/PA66 samples. Both the Al2p and C1s spectra of XPS confirmed the formation of AlOC bonds at the interface between PA66 and alumina coating. Approximately 23.6% of the Al atoms in the 0.8 nm alumina coating have contributed to the formation of AlOC bonds. The carbonyl group at the PA66 surface played an essential role in the formation of such an AlOC bond. The formation of AlOC bonds was proved to be a key factor for achieving good joint strengths in such metal/polymer joints, providing a direct understanding why aluminum alloys can be directly welded to PA66 plates with superior joint strength.

Friction Stir Resistance Spot Welding of Aluminum Alloy to Advanced High Strength Steel

A hybrid friction stir resistance spot welding (RSW) process is applied for joining aluminum alloy 6061 to TRIP 780 steel. Compared with conventional RSW, the applied current density is lower and the welding process remains in the solid state. Compared with conventional friction stir spot welding (FSSW) process, the welding force is reduced and the dissimilar material joint strength is increased. The electrical current is applied in both a pulsed and direct form. With the equal amount of energy input, the approximately same force reduction indicates that the electro-plastic material softening effect is insignificant during FSSW process. The welding force is reduced mainly due to the resistance heating induced thermal softening of materials. With the application of electrical current, a wider aluminum flow pattern is observed in the thermo-mechanically affected zone (TMAZ) of weld cross sections and a more uniform hook is formed at the Fe/Al interface. This implies that the aluminum material flow is enhanced. Moreover, the Al composition in the Al–Fe interfacial layer is higher, which means the atomic diffusion is accelerated.

Strength analysis of single lap dissimilar materials bolted joint

Presently, lot of emphasis is given on joining of dissimilar materials. Around 60-70% of the structures are failing at the joints. Therefore, it is critical to investigate the failure load and failure mode of dissimilar materials joint. The present work investigates the failure of single lap single bolted joints mainly on shear and bending strength. Two material combination joints such as Mild Steel - Aluminum and Mild Steel - Glass fiber reinforced polyesters bolted joints are analyzed using experimental and finite element methods. Present investigation shows that the Mild Steel - Glass fiber reinforced polyesters has better shear strength and bending strength than the Mild Steel - Aluminum material joint.

Joining of magnesium and aluminum alloys via ultrasonic assisted friction stir welding at low temperature

Intermetallic compounds (IMCs) formed in the stir zone (SZ) of dissimilar friction stir welded aluminum/magnesium (Al/Mg) joint always deteriorate tensile properties. Joining of 6061-T6 Al and AZ31B Mg alloys via ultrasonic assisted friction stir welding (UaFSW) at low temperature was performed to reduce the disadvantages caused by IMCs. A sound Al/Mg joint with smooth surface was obtained based on the stationary shoulder at a high welding speed of 80 mm/min, rotational velocity of 1000 rpm, and ultrasonic power of 1400 W due to the improvement of material flow caused by ultrasonic, indicating the success of low-temperature welding. Meanwhile, joining interface, characterized by the IMCs, was attributed to inter diffusion caused by severe plastic deformation from ultrasonic and friction stirring. The tensile strength and elongation of the Al/Mg joint reached 134 MPa and 1.5%, respectively. The IMCs containing Al2Mg3 formed in the SZ was the main reason of tensile fracture, and then resulted in cleavage fracture. The present study suggests that UaFSW has feasible and potential to join Al/Mg alloys at low temperature, which provides a significant reference for welding joint of dissimilar materials with the IMCs.

Dissimilar materials joint between Resin and Metal by using pulse laser aided twin-beam laser

Dissimilar materials joint between Resin and Metal by using pulse laser aided twin-beam laser

異材接合体の強度評価

異材接合体の強度評価

Strength characteristic in aluminium alloy / copper alloy dissimilar materials joint plate produced by friction stir welding and rolling

Strength characteristic in aluminium alloy / copper alloy dissimilar materials joint plate produced by friction stir welding and rolling

Fatigue properties of friction stir welds of treated Al to carbon fibre-reinforced plastic

ABSTRACTThe purpose of this paper is to establish the welding technology for dissimilar materials of carbon fibre-reinforced plastic. Therefore, this study focused on friction stir spot welding, which can be simply substituted for spot welding which is widely used for welding of automobile body. In this study, friction stir spot welding was used to weld joints of carbon fibre-reinforced plastic and aluminium alloy, and the effect of aluminium alloy surface treatments on the fatigue properties and the fracture mechanism of dissimilar material joints were investigated experimentally and statistically. As a result, it is possible to create welding joints with high fatigue durability by using the surface treatments on the aluminium alloy.

Strength Characteristic of SUS304/PET Dissimilar Materials Joint Joined by Pulse Laser Aided Twin Laser Beam

Strength Characteristic of SUS304/PET Dissimilar Materials Joint Joined by Pulse Laser Aided Twin Laser Beam

Producing aluminum alloy / copper alloy dissimilar materials joint plate by using friction stir welding

Producing aluminum alloy / copper alloy dissimilar materials joint plate by using friction stir welding

Effect of deterioration in resin on strength characteristic of resin / metal dissimilar materials joint

Effect of deterioration in resin on strength characteristic of resin / metal dissimilar materials joint

Influence of the degree of dilution with laser beam vacuum-welded Cu-Al mixed joints on the electrical properties

A great potential for light-weight construction lies in the substitution of copper by aluminum. The state of the art, so far, has put the focus only on the identification of the crack-sensitive intermetallic phase.External influential factors, such as temperature, current-feed and time bring about the change of the joining zone structure by diffusion and electro-migration. Moreover, a temporal change of the technological properties (increase of the electric resistance, reduction of strength) of the dissimilar material joint will occur. Findings about this behavior for laser beam under vacuum welds will allow to draw conclusions about the expected life-time.

Friction stir girth welding between aluminum and steel rods

Friction stir welding is enable to fabricate dissimilar materials joint which is difficult for conventional fusion welding. Thus, the method is promising way to fabricate multi-material structure for achieving weight reduction and high functionalization. Lap welding with spot weld (0D shape), butt welding with linear weld line (1D shape) and curved weld line (2D shape) were achieved for dissimilar welding between aluminum and steel. From the study, the shape change of weld line influence on heat input, material flow, and the process window of welding. The weldability with 3D shape weld line was investigated by friction stir girth welding between aluminum (AA6063) and steel (S45C) rods with 53 mm in diameter. It was difficult to fabricate defect free weld by friction stir girth welding without tool tilt angle. However, defect free weld was fabricated by friction stir girth welding with tool tilt angle. From the observation of material flow in the weld by X-ray CT, optimum material flow is generated in the weld. During welding, welding force and temperature increased with rotation of weld materials. These affected to the microstructure of weld with increasing the area of HAZ and softening the microstructure of weld. Fracture strength was 63.5 kN, and weld strength was about 117 N/mm2 and slightly lower than the strength of base metal.

Effect of change in mechanical properties of resin on strength characteristic in resin/ metal dissimilar materials joint

Effect of change in mechanical properties of resin on strength characteristic in resin/ metal dissimilar materials joint

The Role of Mechanical Connection during Friction Stir Keyholeless Spot Welding Joints of Dissimilar Materials

Contrast experiments of lap joints among dissimilar AZ31B Mg alloy, Mg99.50, zinc-coated DP600 sheet, and non-zinc-coated DP600 sheet were made by friction stir keyholeless spot welding (FSKSW) and vacuum diffusion welding (VDW), respectively. Scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS) were used to investigate the microstructures and components of the joints welded. The experimental results show that the FSKSW bonding method is a kind of compound mode that contains a mechanical connection and element diffusion fusion connection, in which mechanical connection has the main decisive function on joints of Mg/steel. Elements diffusion exists in the interfacial region of the joints and the elements diffusion extent is basically the same to that of VDW. The elements’ diffusion in Mg/steel using FSKSW is defined in the reaction between small amounts elements of the base metal and zinc-coated metals. The intermetallic compounds and composite oxide perform some reinforcement on the mechanical connection strength.

Formability assessment and failure prediction of laser welded dual phase steel blanks using anisotropic plastic properties

Assessment of the role of weld zone and difference in the material properties across the dual phase steel tailor welded blanks (TWBs) during sheet forming is imperative prior to applications in light weight auto-bodies. In the present work, one laser welded blank (LWB) of similar material combination and two different TWBs were fabricated by laser welding of dual phase steels (DP600, DP980) and interstitial free (IF) steel. The quality of the laser welded similar (DP600-DP600) and dissimilar material (DP600-DP980 and DP600-IF) joints were evaluated in terms of metallographic observations, hardness studies and tensile tests. Evolutions of microstructures within the vicinity of weld region were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, the local property changes in the weld regions were observed through micro-hardness and nano-indentation tests. The formability performances of above three welded blanks were evaluated under different deformation modes using three case studies such as Erichsen cupping, deep drawing and double-stage forming tests. It was observed that the formability of DP600 LWBs decreased by 28% due to the presence of weld in comparison to that of the monolithic parent material. In case of TWBs, the weld line movement was observed causing non-uniform deformation and failure at weaker side. The FE models of the above three case studies were developed incorporating Yld2000-2d anisotropy constitutive properties of the parent metal and further considering the properties of the non-homogeneous welded zone. The Marciniak-Kuczynski model and thickness gradient based necking criterion were both applied to predict the failure successfully in the FE model, and the results were validated with experimental data to establish the robustness of both the failure models.

Process characteristics and load-bearing capacities of joints welded with elements for the application in multi-material design

In the global market of the engineering sector, products can only be economically successful when they are extraordinarily light, safe, environment-friendly, and favorable compared to the competitors’ products. Because of new regulations for the reduction of CO2 emissions, especially the automotive industry is increasingly focusing on weight reduction in the car body structure through multi-material design with high-strength steels and aluminum. Conventional joining technologies for the body shop are often not applicable for these dissimilar material joints, for which reason new technologies must be invented. The hybrid thermal-mechanical joining technologies “resistance element welding” and “friction element welding” have been invented in recent years and are suitable for the high-volume production of multi-material structures with ultra-high-strength steels. Multi-material joints require effective corrosion protection measures. This paper presents how suitable process parameters can be determined for these two innovative technologies. Moreover, it shows the influence of a zinc-based anticorrosive fastener coating on the process parameters, the load-bearing capacity, and the corrosion behavior of the joints.

表面処理を施した金属と樹脂の異材接合体の局所的な界面強度評価

表面処理を施した金属と樹脂の異材接合体の局所的な界面強度評価

異種材料接合継手の強度評価手法の開発

異種材料接合継手の強度評価手法の開発

Evaluation of interfacial strength by indentation test in resin/metal dissimilar materials joint

Evaluation of interfacial strength by indentation test in resin/metal dissimilar materials joint