Dissimilar Metal Joining Research Articles

A Review on Joining of Dissimilar Metals with Highly Differential Thermomechanical Properties

A Review on Joining of Dissimilar Metals with Highly Differential Thermomechanical Properties

A comparative study of friction stir welding and friction stir scribe technique for dissimilar metal joining

Abstract Friction stir welding (FSW) has emerged as a novel method for joining similar and dissimilar ferrous and non-ferrous materials. This solid-state welding process utilizes frictional heat generated between a tool shoulder and the base material. The stirring action facilitates the movement and consolidation of the material, resulting in localized fusion and the formation of a joint. This review examines their effectiveness in joining various material combinations, with particular focus on automotive and aerospace applications. FSW utilizes frictional heat and stirring action to create localized plasticity and material flow, while FSS incorporates a cutting feature to mechanically interlock dissimilar materials. The review paper shows comparison of various experimental investigations considering variables such as tool geometry, welding parameters, and material combinations. FSW has some significant parameters to enhance weld quality such as traverse speed, plunge depth, and tool design. These techniques show promising applications for multi-material integration, offering advantages over conventional fusion welding methods. Future research directions include expanding material combinations, developing automated systems, and exploring hybrid joining approaches.

Optimization of TIG welding process parameters using Taguchi technique for the joining of dissimilar metals of AA5083 and AA7075

This research paper aims to optimize the TIG welding parameters to join dissimilar metals of AA5083 and AA7075 using the Taguchi technique. The TIG welding current and root gap of butt geometry configuration are considered input parameters, and welding characteristics such as tensile strength, 0.2% of yield strength, hardness, and impact energy are output responses. The base metals are joined according to the Taguchi L-09 design of experiments. The welded samples were inspected using the X-ray radiography method for internal defects. Tensile properties, hardness number, and impact energy of different welding coupons were evaluated by conducting the uni-axial testing, a Brinell hardness test, and an Izod impact test, respectively. A better weld strength of 224 MPa was observed at 210 A welding current, and the root gap of 1.5 mm was maintained. Better hardness and impact energy values were observed when the root gap of 1.5 mm and welding current of 220 A were maintained. The root gap is the primary factor influencing tensile strength enhancement, which accounts for 44.78% of the effect, followed by 40.5% welding current. Root gap is the parameter that affects the tensile properties, hardness number, and impact toughness the most. The findings of this paper suggest the optimal parameters for welding AA5083 and AA7075 dissimilar base metals, which are suitable for complex structures requiring both durability and resistance to harsh environments.

Microstructure, Mechanical and Fractographic behaviour of the Diffusion Welded Joints of AA2219 and Ti-6Al-4V for Propellant Tank Applications

Diffusion welding is an advanced joining process that assures the feasibility of joining dissimilar metal alloys without producing metallurgical impurities at the joint interface. Two significant aerospace alloys, AA2219 and Ti-6Al-4V, are diffusion welded for the various holding times (30-120 minutes) by keeping the bonding temperature and pressure constant. The effect of holding time on the microstructure of the diffusion welded joints is evaluated using scanning electron microscopy (SEM), and the diffusion behaviour across the joint interface is ensued by the line scan energy dispersive spectroscopy (EDS). The obtained results show that the hardness across the joint interface is increased with increase in holding time. Furthermore, the maximum shear strength of 143.58 MPa is achieved for the joint formed at the holding time of 90 minutes and reduced thereafter. The formation of a thick intermetallic layer at a higher holding time strongly affects the shear strength. It is evident from the resulting fractured surfaces that the joints predominantly failed at the bonding interface, showcasing the brittle kind of failure. The X-ray diffraction (XRD) study on the fractured surfaces substantiates the formation of AlTi, Al2Ti and Al3Ti intermetallic compounds.

Dissimilar joining of Ti–6Al–4V to 316L stainless steel by a novel joining process based on arc additive manufacturing and combined twin-wire arc welding

The joining structure of Ti–6Al–4V to 316L stainless steel has potential demands in many fields. However, it is very difficult to avoid the formaiton of intermetallic compounds (IMCs) of the weld between Ti–6Al–4V to 316L stainless steel, which will severely decrease joint properties. In this paper, a novel joining technology that combines the single wire backing arc welding and the spatially arranged combined twin-wire arc welding was utilized to join Ti–6Al–4V and 316L stainless steel. Copper alloy wire (S214) and vanadium alloy wire (V01) were used as filler metals to produce two isolation layers, which prevented the formation of IMCs. The phase compositions at the Fe/Cu, Cu/V and V/Ti interfaces were Fe(S,S) + Cu(S,S), Cu(S,S) + V(S,S) and V(S,S)+(β-Ti, V)SS respectively. The distribution of the spherical and clustered V(S,S) particles in the matrix at the Cu/V interface contributes to dispersion strengthening and solid solution strengthening of the interface. Tensile strength of 394 MPa with an elongation of 2.53% was achieved. The joint fractured at the Cu/V interface of the single wire backing arc weld and the Cu zone of the spatially arranged combined twin-wire arc weld respectively. Dimple plastic fracture modes were detected in the joints. This technology is not only applicable to Ti–6Al–4V titanium alloy/316L stainless steel dissimilar metal joining, but also provides a new research strategy for the joining between other dissimilar metals.

Role of Activating Flux in Weld Bead Symmetricity during Dissimilar Metal Joining

Ferritic/martensitic steels and austenitic stainless steels are high‐strength steels, and highly recommended in high‐temperature and high‐pressure application. In general, multimetallics with different Inconel alloys are used for joining. This is quite a complex and time‐consuming procedure. The current work demonstrates the efforts made to weld 8 mm‐thick P91 steel and 316L SS plates in a single pass using activating flux tungsten inert gas (A‐TIG) welding process without any interlayers. The main challenge is to get the symmetric weld bead profile. Flux coating is optimized in terms of flux composition, coating density, and coating pattern to get the full penetration with symmetric appearance. The current work discusses the possible cause and their solution of asymmetricity during dissimilar welding. Differential flux coating density is found to be very effective in controlling the arc column shape, fluid flow, and consequently the bead geometry. High coating density is used in the P91 side compared to 316L side. Symmetric weld profile with full penetration is achieved by applying multicomponent flux (33–38% TiO2, 38–43% SiO2, 13–17% NiO, and 8–10% CuO) during A‐TIG welding.

Design method of immiscible dissimilar welding (Mg/Fe) based on CALPHAD and thermodynamic modelling

Joining dissimilar metals is a major challenge in joining technology; the weldability of immiscible systems is especially challenging. In this study, a design methodology for dissimilar welding is suggested. The Miedema model and Toop model are developed to calculate the thermodynamics of quaternary alloy systems (Mg-Fe-Al-Cu). Finite element modelling (FEM) of temperature fields and the calculation of phase diagrams (CALPHAD) are combined to provide prerequisite information for modelling. As a test subject, laser welded lap configuration joints of AZ31B magnesium alloy and DP590 steel with a copper coating were put into the design scheme. The interfacial elemental diffusion and formation of intermetallics (IMCs) along the interface during the welding process are predicted. This simulation design scheme predicts the interfacial reaction kinetics and identifies whether the intermediate element works or not. The effects of the Cu coating thickness on the weld constitution, interfacial microstructures and mechanical properties were studied. Cu coating promotes the weld formation fostering the metallurgical reaction of the fusion zone (FZ) with the steel brazing interface. The mechanism of interfacial reactions during the welding-brazing process has been clarified. The Vickers hardness distribution across the interface shows that the Cu-IMCs are ductile.

An Analysis of Laser Welding Technology used for Joining Dissimilar Metals, Computational Parameters and Challenges

Welding particularly joining dissimilar metals is new technology. Laser welding is a challenging task and most essential and reliable method of joining dissimilar metal used in various industrial area. Out of the modern welding laser welding is gaining its popularity due to its various unique features. Laser welding, is modern method of joining similar or dissimilar parts metal/non-metal by laser beam of very high power, high temperature source. Very good control on input factors, very small heat affected zone, precise accurate welding joint and high speed are some attractive features of this technique. This technology gives more flexibility to design engineer. Various kind of lasers such as Nd:YAG, Co2 laser, Diode laser, disk laser m/c are used in welding of automobile, aerospace and ships. All concept of laser welding depends on the key-hole phenomena. It is a cavity formed by recoil pressure and energy absorption is due to high temperature multi reflection of laser rays. So this gives deep Penetration of weld joint. This paper shows various Challanges of dissimilar metal welding and technique to over come this. In our use study We are going to use dissimilar metal plates of 3.5 mm thick of 16MnCr5 and 316 SS. This metal jonts are used in production of automotive cylindrical part in large quantity.

EFFECT OF ELECTRODE ON JOINING TWO DISSIMILAR METALS (SS & MS

This study examines the challenges associated with joining dissimilar metals, specifically stainless steel and mild steel, and investigates the impact of electrode selection on joint quality and characteristics. Various welding processes, including shielded metal arc welding (SMAW), is explored. Experimental findings indicate that electrode choice significantly influences the formation of intermetallic compounds, fusion zone morphology, and mechanical strength of the joint. Alloying elements in electrodes are found to enhance weldability and performance by facilitating metallurgical bonding and reducing the formation of brittle phases. Furthermore, the study explores variations in welding parameters to optimize the process for desirable joint properties. By deepening our understanding of electrode roles in welding dissimilar metals, this research offers insights crucial for selecting appropriate techniques and parameters, ensuring reliable joints. These insights have broad applicability across industries such as automotive, aerospace, construction, and manufacturing, where dissimilar metal joining is common. Key Words: dissimilar metals, intermetallic compounds, Weldability, morphology, mechanical strength.

Effect of Friction Pressure on the Mechanical Properties of CDFW Dissimilar Aluminium 6061-T6 and Stainless steel 304 Welding Joints

Welding technology has significantly developed in the industrial sector along with advances in manufacturing technology. The demand for joining methods combining dissimilar metals is increasing in the industrial sector. However, joining dissimilar metals is challenging because of differences in physical and mechanical properties. Continuous drive friction welding is a solid-state joining method widely used to join dissimilar metals. The research aimed to determine the effect of variations in friction pressure on the mechanical properties of continuous drive friction welding joints with dissimilar materials, Aluminum 6061 T6 and Stainless Steel 304. The process parameters used in this welding were the friction pressures used were 30 MPa, 35 MPa, and 45 MPa. The friction time is 2 seconds, the rotation speed is 1000 rpm, and the upset pressure is 50 MPa. Then, welded joints were evaluated for Vickers microhardness and microstructure observations. Based on the research results, it shows that the temperature distribution and microstructure results show that there is a change in the hardness value of the aluminum material. In contrast, the 304 stainless steel material experiences an insignificant change in the hardness value.

Metallurgical and mechanical properties evaluation of the activated flux tungsten inert gas weldments

The activated flux tungsten inert gas welding process is an attractive joining technique to increase the depth of penetration in a single pass. In the last two decades, the research on activated flux tungsten inert gas welding increased drastically. Despite enhanced weld penetration, activated flux tungsten inert gas is not frequently implemented in industries because of a lack of information about the process. However, research on activated flux tungsten inert gas welding has significantly increased in the last decade due to the widespread information related to the advancements in weld penetration and mechanical properties of the activated flux tungsten inert gas process. The activated flux tungsten inert gas welding process provides a high single pass depth of penetration along with good mechanical properties compared to the tungsten inert gas welding process. The current work offers an in-depth analysis of the activated flux tungsten inert gas welding process mechanism, advancement in activated flux tungsten inert gas methodology to improve weld bead geometry, and mechanical and corrosion behaviour of the weldments. The current work also highlights recent progress made in the field of dissimilar metal joining using the activated flux tungsten inert gas welding process.

Al-Cu intermetallic phase growth in hybrid metal extrusion & bonding welds exposed to isothermal annealing or direct current cycling

Joining of aluminium (Al) to copper (Cu) is of great interest to power generation, transportation and electronic industry. However, dissimilar metal joining often promotes intermetallic phase formation at the joined interface, which in redundancy can cause mechanical degradation and increased electrical resistance. The welding technique hybrid metal extrusion & bonding (HYB) is proven capable of joining dissimilar metals with a total intermetallic phase layer thickness <▪. To test how Al-Cu HYB joints perform as electrical conductors, a 6101 Al alloy HYB-welded to Cu is exposed to heat treatment at ▪ or cycling of direct current density up to ▪. In-depth micro- and nanostructure characterisation by (scanning) transmission electron microscopy and atom probe tomography are used to describe the structure and chemistry of the formed intermetallic phases.The Al-Cu HYB joints exhibited resilience against intermetallic phase growth during isothermal heat treatment or exposure to electric current. However, a non-symmetry is observed dependent on the current direction, creating voids in Cu near, and in the intermetallic layers when the current goes from Al to Cu. Detailed microstructure characterisation unveils Si and Mg in the intermetallic phase layers. Their origin and role in intermetallic phase growth are discussed.

Study on process, microstructure and mechanical properties of 6061/AZ31 dissimilar metal joining with direct contact reaction brazing

In this study, 6061-Al and AZ31-Mg were successfully joined using the contact reaction brazing process without an interlayer under a pressure of 2 MPa and a vacuum of 1 Pa. The study examined the microstructure and mechanical properties of 6061/AZ31 joints, as well as the impact of process parameters including heating mode, cooling rate, heating temperature, and holding time on the joints. The results show that the 6061/AZ31 brazing seam can be divided into two zones: the liquid-phase solidification zone and the diffusion reaction zone. The liquid-phase solidification zone consists of the (α-Mg + Al12Mg17) eutectic organization and precipitation phases distributed therein. The diffusion reaction zone mainly consists of the Al3Mg2 layer in the brazing seam close to the 6061. Fractures in joints mainly occur in the diffusion reaction zone, where the hard and brittle Al3Mg2 layer is located and extends into the liquid-phase solidification zone. Brazing joint quality was better with a cooling rate of 5 °C/s and heating without pre-weld and post-weld holding processes. The highest joint shear strength of 37 MPa was achieved at 445 °C with a holding time of 5 s. The joint exhibited no obvious defects, and the axial shrinkage of the specimen was 0.414 mm, with minimal deformation.

Testing and evaluation on friction surfacing of Alloy 36 over spheroidal graphite iron and its effect on coating thickness and width using artificial neural networks and response surface methodology

AbstractFriction surfacing finds its application in areas which require joining of dissimilar metals with superior wear property. The current work investigates the solid‐state coating of Alloy 36 over ductile cast iron (SG Iron) by friction surfacing process. The effect of process factors on the actual geometry of the coating was investigated through testing and a desirability‐based technique. Spindle speed, axial force, and table traverse speed were the three most important variables for bonding fidelity. Analysis of variance was used to examine how the input parameters affected the output parameters. Experimental findings are validated using artificial neural networks and response surface methodology which are then used to predict how the system will respond to various operating scenarios. The research demonstrates that speed, rather than force or traverse action, has a more substantial effect on both materials. The response surface methodology statistician approach was utilized to identify the most important factors influencing the process parameters. As a result, the load is determined as the most crucial component that impacts bonding to the substrate. According to the data, the output parameters have the most impact on lowering the bonding geometry.

Evolution of bonding mechanism and fracture mechanism of Ti alloy-steel joint by dual-beam laser welding using Mg-RE (RE=Gd, Y) filler

In this paper, a novel coaxial continuous-pulsed dual-beam laser was proposed to join TC4 titanium alloy with QP980 high-strength steel, and magnesium alloy containing rare-earth elements (Mg-RE) was creatively as filler. The weld appearance, microstructure and mechanical properties of joints obtained by single-beam and dual-beam laser welding were compared and analyzed. And the evolution of bonding mechanism and the fracture mechanism with laser beam energy density was analyzed. The results showed that the appearance and mechanical strength of the joint obtained by dual-beam laser were better than that by single-beam laser. And the maximum tensile shear load of TC4/QP980 lap joint welded by dual-beam laser reached 303 N/mm, which was 124 % of that of single-beam laser welding. The bonding of Mg-RE with QP980 affected by temperature of laser welding and mainly depended on Gd and Y. They just diffused to QP980 under low power and reacted with Fe under high power. And the inter-diffusion of Zr of Mg-RE with Ti of TC4 produced to the bonding of Mg-RE with TC4. The roles of continuous laser and pulsed laser in dual-beam laser welding were revealed in this paper and it showed a great application potential of coaxial dual-beam laser welding technology in dissimilar metal joining.

Analysis and Design of a Pulsed Power Generator for a Low-Energy Magnetic Pulse Welding System

Magnetic pulse welding (MPW) is a joining method that uses Lorentz force generated from an electromagnetic field. This method not only has the advantage of not causing thermal deformation of the material and no by-products compared to the method of joining by melting by heat but also enables the joining of dissimilar metals rather than the joining of the same metal. Joining dissimilar metals can reduce the weight of mechanical devices and apply them to various fields. Recent research on MPW has focused on the characteristics of bonding according to the material or structure of metal rather than on pulse power research that generates the main factor of operation. However, in the operation of MPW, a Lorentz force is generated by the induced current caused by the electromotive force created in the flyer tube and the external magnetic field in the actuator. Therefore, it is necessary to analyze and optimize the pulse power to improve reliability and to miniaturize the system to expand the MPW utilization range. In this paper, we analyzed MPW operation according to a section of the pulse power output waveform. A condition for obtaining the maximum current in the flyer tube was proposed, and a plateau-shaped waveform was derived as an ideal output waveform capable of maintaining the Lorentz force. Through analysis, the proposed pulse power device is designed as a pulse-forming network (PFN) that generates a plateau output waveform. The design specification is that the circuit of PFN (type E) is designed so that the output waveform is pulse width 10 (μs) and the maximum output current is 100 (kA), and it is verified by simulation.

Investigation of dissimilar metal (stainless steel and copper) joining and the effect of offsetting and other welding parameters

Dissimilar metal joining without additional preparation like preheating and grooving using conventional arc welding processes. The challenges related to dissimilar joints are overcome by using proper heat distribution according to the heat requirement of different plates. In the present study, GTAW is used to join SS and Cu, mode of joining is welding-brazing mode on the SS side. The heat distribution is done by offsetting the arc towards the Cu side because of the high thermal diffusivity of Cu compared to stainless steel (SS). For the complete joining, the 2nd pass is done without offset. A “beach” of unmixed Cu metal along the Cu fusion line and “peninsula” of an unmixed SS in the weld metal is observed in the microstructure. The grain size variation is observed in the different zones of the weldment due to the segregation of SS particles in weldment. The joint integrity is analyzed with an optical microscope image of the bead, and the detailed analysis of weldment is done using FESEM images in BSD mode. From the microstructure porosity and Cu, penetration is observed in the SS side mushy zone. The microhardness of the weld bead is utilized to see the effect of grain size and amount of SS particles on the mechanical property of weldment in the different zone of the weld bead. The tensile test is conducted to study the joint property of the test coupon. The joint strength of Joint-7 is 225 MPa and percentage elongation is 17 percent, efficiency obtained is around 85 per cent of the Cu plate.

Evaluation of dissimilar metal joining of Al/steel by in-situ formation of a copper barrier interlayer

The utilization of pure copper powder as a filler material in dissimilar metal laser welding of Al/steel was investigated in this study. The microstructure and tensile properties of the welded joint were analyzed, and the thermodynamics of microstructure formation within the weld zone were discussed. The results revealed that pure Cu powder successfully facilitated the in-situ formation of a barrier interlayer between aluminum and steel, effectively impeding the generation of Fe-Al intermetallic compounds. Notably, the weld zone near the Al base metal exhibited a eutectic zone comprising α-Al + Al2Cu eutectic structures, along with a thin layer of Al4Cu9 phase. Consequently, the dissimilar joint achieved a well-formed weld and exhibited a tensile strain capability of ∼ 6 %, with the fracture occurring in the Al base metal.

Effect of a ring-shaped laser beam on the weldability of aluminum-to-hilumin for battery tab connectors

Advances in laser beam shaping technologies are being studied and are considered beneficial in many aspects of dissimilar metal joining, which include reducing intermetallic compounds (IMCs), optimizing weld pool profiles, and controlling porosity and spatters. This paper utilizes a coaxial ring and core dual beam laser and aims to study the impact of the power ratios between core and ring beams on the weldability of 1100 aluminum alloy to hilumin (steel). High-resolution electron microscopy was performed in the cross sections of the weld pools to quantify the melt pool composition and subsequent IMC formation and weld defects (cracking and cavitation). Lap-shear mechanical testing and electrical resistivity testing were also carried out. Results showed that the optimal power ratio for lap-shear strength was 0.4 (intermediate core and ring) due to the reduction in the Fe-rich liquid into the upper weld region. As a result, this produced a smaller interface between the Fe-rich region and Al, thus reducing the formation of the most detrimental IMC (e.g., Fe2Al5). Conversely, a power ratio of 0.2 (core-dominant) was found beneficial for reducing electrical resistance due to a reduced total IMC volume.

Development of a comprehensive model for predicting melt pool characteristics with dissimilar materials in selective laser melting processes

Selective laser melting (SLM) is a popular additive manufacturing (AM) technique for the fabrication of precise components. The success of SLM relies on accurate control of the melt pool, where the metal powder melts and solidifies. Fluid flow inside the melt pool is driven by forces like Marangoni force and recoil pressure. SLM process begins with the fabrication of support, which involves the process of joining dissimilar metals. A strong support-base substrate connection ensures the success of subsequent additive manufacturing. In this study a comprehensive model was developed to predict the dimensions and characteristics of the melt pool with a focus on the first layer of the SLM process. An initial numerical simulation was done to obtain transient melt pool temperature and velocity distribution during the SLM process. The results were then coupled with a theoretical analysis development of the proposed model. The effectiveness of the model was validated by experimental results and melt pool characteristics from previous publications. The model shows Root Mean Square Error (RMSE) of 0.53 and 0.49 for height-to-width ratio and normalized area, respectively. The Mean Absolute Percentage Error (MAPE) of normalized area is 15.7% for the majority of the data, which demonstrates a good accuracy of the model. In addition, the transition from conduction mode to keyhole mode can be identified with the model. This model can be used to rapidly and effectively predict the melt pool characteristics for SLM and other similar AM processes with a wide range of processing parameters.