Dissimilar Joining Research Articles

Resistance Element Welding (REW) of Steels with Non-Ferrous Materials: Potentials, Challenges, and Properties

Performance and functionality are two key factors in designing advanced components. One promising approach in manufacturing design is the fabrication of multi-material structures by joining dissimilar materials. Steels, known for their outstanding properties and cost-effective production, are widely used across several industries. However, their high density presents challenges when designing lightweight components. A solution lies in combining steels with lightweight, non-ferrous alloys to develop cost-effective multi-material parts. However, joining different materials is generally complex due to their different properties, making it sometimes challenging or even unfeasible. Resistance element welding (REW) offers a high-performance alternative to traditional methods, such as resistance spot welding, with a high potential in mass production industries like automotive manufacturing. This article comprehensively reviews the latest research on REW for dissimilar joining of steels and non-ferrous alloys. It focuses on the microstructural and mechanical properties of joints, innovations in the REW process, the influence of process parameters on joint quality, as well as simulation and numerical studies. In addition, REW is compared with traditional joining methods.

Advancements in Laser Beam Welding for Dissimilar Material Joining: Exploring Weldability Assessment, Challenges, Parametric Influences on the Mechanical–Microstructural Properties in Steel‐Alloyed Metal Combinations

With the growing demands in several sectors such as the automotive, biomedical, construction, shipbuilding, aerospace, and other manufacturing units, employment of welding techniques has observed a rapid boom in recent times. Laser welding technique is one such recent sign of progress in the fabrication field. Laser beam welding is a radiant energy welding process widely adapted to join a variety of metals and nonmetals. The demand for the dissimilar material welding increases with the increase in industrial needs. Several severe challenges need to be overcome to have such dissimilar welded components mainly as the significant difference in melting point, different combinations of mechanical, metallurgical, chemical, and thermal properties. The present approach attempts to study the weldability of steel and its alloys with other metals and parametric effects on mechanical and microstructural properties. The study reveals that the laser beam offset plays a vital role to achieve sound quality welded joint with desirable weld strength. It has been found that 0.32 mm beam offset generates 243 MPa ultimate tensile strength in the 316L to TC4 dissimilar welds. Again, the addition of interlayers also improves the joint strength of both steel‐to‐aluminum and steel‐to‐titanium dissimilar welded joints.

Achieving superior aluminum-steel dissimilar joining via ultrasonic spot welding: Microstructure and fracture behavior

High-strength dissimilar welded joints of AA2024-T3 alloy with an AA1230 coating and galvanized high-strength low-alloy (HSLA) steel were attained through ultrasonic spot welding (USW) in this study. The tensile lap shear failure loads over a welding energy range between 2000 J and 3000 J were observed to meet or surpass the values specified in the AWS D17.2 standard. The highest average tensile lap shear strength was obtained to be ∼169 MPa due to the formation of a ∼30–70 μm thick Al-Zn diffusion layer without the presence of intermetallic compounds. The substrate failure from the softer AA1230 coating on the AA2024 side under tensile loading and cyclic loading at higher cyclic loads was observed, which reflected a robust sticking capability. The partial failure from AA1230 coating consisted of characteristic shear dimples, allowing high plasticity upon shear deformation. While the 1000 J welds failed mainly via substrate failure from AA1230 and transverse through-thickness (TTT) cracking in AA2024, the cohesive failure across the Al-Zn diffusion layer and adhesive failure from the Al-Fe-intermetallic/Al-Zn-diffusion layer interface were observed in the welds made at 3000 J, corresponding to the superior bonding strength and longer fatigue life.

Evaluation of Tensile Strength of Dissimilar Metals SS 316-pure Zn Joining by Friction Welding Method

Welding of dissimilar metals has always been a challenge in industrial applications. In this study, the joining of SS 316 and 99.9% pure zinc by continuous drive friction welding has been carried out. The welding process is carried out with parameters such as rotation speed, friction pressure, forging pressure, and burn length being kept constant for all weld joint samples. This friction time is selected through the process parameter approach carried out on aluminium alloy material. The experimental results were analysed by tensile test and microstructure using a scanning electron microscope (SEM) to characterise the microstructure. Tensile test results from friction welding with variations in friction time from 30 to 80 seconds obtained a higher tensile strength of the joint in the 30 to 50 seconds friction time range. In this experiment, the maximum joint tensile strength is obtained at 53.93 MPa, and the maximum modulus elasticity of 128.60 GPa at 35 seconds of friction. Solid-state welding makes it possible to join SS 316 and pure zinc, which is difficult to join in conventional fusion welding methods.

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.

Pure copper coating by multibeam directed energy deposition with blue lasers for antimicrobial effect

Pure copper has antimicrobial effect, and the development of pure copper coating technology for product surfaces is needed to prevent the spread of infections. To achieve high antimicrobial performance in coatings, it is essential to form a coating with high copper purity and minimal defects. In this study, we attempted to form a pure copper coating layer on a SS304 substrate using multibeam directed energy deposition with blue diode lasers. In the coating layer formation process, multiple bead layers are overlapped to form a smooth surface and two different types of joining is conducted simultaneously: the similar material joining area with the remelted previous layer, and the dissimilar-material joining area with the substrate. However, it was challenging to conduct this process for SS304 and pure copper due to their significantly different thermal properties. Therefore, we varied the hatching distance to control the heat input to both joining areas and investigated the effect on the quality of the coating layer. The results showed that there is an optimal ratio of similar and dissimilar joining areas, at which a high-quality coating layer with few voids and low dilution is formed. Furthermore, antimicrobial tests showed that the pure copper coating layer formed in this study exhibited the antimicrobial performance equivalent to those of a pure copper plate.

Effects of temperature and stress evolution on microstructural change and mechanical properties during friction element welding

Dissimilar material joining is essential for improving the strength-to-weight ratio of materials for various applications. Friction element welding (FEW) is a promising solution for joining highly dissimilar materials that vary in strength and thickness. However, the influence of the process parameters on the material’s resultant microstructure and mechanical properties remains unclear. In this study, the relationship between microstructure and microhardness distribution of the welded specimen is experimentally studied, and the effects of temperature and stress evolution are revealed by a thermal–mechanical finite element model. It is found that the microhardness can be improved by over 50% in the central region due to microstructural change and grain refinement. The beneficial microstructural change can be achieved by inducing either a high peak temperature (over the austenitization temperature) or a high peak stress (over the hardening factor) during the FEW process, which can be obtained by controlling the endload and rotational speed of the friction element. The size of the region with improved hardness is observed to vary with the depth of deformation in the steel layer. For the transverse shear strength (TSS), it is observed that irrespective of the temperature levels reached, TSS increases with increasing stress in the steel layer. Temperature plays a crucial role when the steel layer’s temperature is higher than the austenitization start temperature wherein TSS increases with the temperature.

Dissimilar joining of aluminum alloy and low-alloy carbon steel by resistance spot welding

In this work, the resistance spot welding (RSW) process was performed to join aluminum alloy and low-alloy carbon steel plates. The macro characteristics including nugget diameters and indentation rates, microstructure and tensile-shear strength of RSW joints were investigated. The results showed that the nugget of the RSW joints comprises a ‘bowl’ shape nugget on the aluminum side and an elliptical shape nugget on the steel side. Also, the intermetallic compound (IMC) layers containing Fe4Al13 and Fe2Al5 were formed around the aluminum/steel interface with the steel side having a tongue-shape and the aluminum side having a needle-shape. According to metallurgical evaluation and temperature distribution of RSW joints analyzed by the finite element method, the nugget on the aluminum side contained the dendritic grains and equiaxed dendritic grains. The nugget on the steel side consisted of a large amount of bainite and a small amount of coarse lath martensite. The nugget diameters and the indentations rates of RSW joints increased when increasing either welding current or welding time, and decreased when increasing the electrode pressure. The maximum values of nugget diameter and indentation rate of RSW joints were 9.076 mm and 4.144% when using the welding current of 16 kA, welding time of 450 ms and electrode force of 3 kN. In tensile-shear tests, the RSW joints showed a shear-off fracture mode. When increasing the welding current, welding time or electrode force, the tensile-shear strength of RSW joints increased first, and then reached a maximum, and finally decreased. The welding current of 16 kA, the welding time of 300 ms, and the electrode pressure of 3 kN were considered as the optimal welding parameters in the present study which resulted in the maximum tensile-shear strength of 2.24 kN. In addition, the IMC layers of the RSW joints exhibited a uniform and continuous appearance with a thickness of approximately 1.9 μm, and the IMC layer in the central area was thicker than that in the edge area.

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.

Study on Laser Transmission Welding Technology of TC4 Titanium Alloy and High-Borosilicate Glass.

As the demand for high-performance dissimilar material joining continues to increase in fields such as aerospace, biomedical engineering, and electronics, the welding technology of dissimilar materials has become a focus of research. However, due to the differences in material properties, particularly in the welding between metals and non-metals, numerous challenges arise. The formation and quality of the weld seam are strongly influenced by laser process parameters. In this study, successful welding of high-borosilicate glass to a TC4 titanium alloy, which was treated with high-temperature oxidation, was achieved using a millisecond pulsed laser. A series of process parameter comparison experiments were designed, and the laser welding behavior of the titanium alloy and glass under different process parameters was investigated using scanning electron microscopy (SEM) and a universal testing machine as the primary analysis and testing equipment. The results revealed that changes in process parameters significantly affect the energy input and accumulation during the welding process. The maximum joint strength of 60.67 N was obtained at a laser power of 180 W, a welding speed of 3 mm/s, a defocus distance of 0 mm, and a frequency of 10 Hz. Under the action of the laser, the two materials mixed and penetrated into the molten pool, thus achieving a connection. A phase, Ti5Si3, was detected at the fracture site, indicating that both mechanical bonding and chemical bonding reactions occurred between the high-borosilicate glass and the TC4 titanium alloy during the laser welding process.

Surface physics and chemistry of carbon fibers enhance dissimilar sheet joining of carbon fiber-reinforced plastic by copper electrodeposition

Carbon fiber-reinforced plastic (CFRP) sheets were dissimilarly edge-joined with anodized A6061 Al alloy sheets by copper electrodeposition. A high bonding strength of 137 MPa was attained following a series of pretreatments including etching in KMnO4 + NaOH hot aqueous solution, anodization at 2 V vs. SUS316 cathode in 1 mol L˗1 H2SO4, and sulfonation in hot concentrated H2SO4. The anodization physically cleaned the carbon fiber (CF) surface in CFRP. The chemical surface properties of the CFs were modified by the anodization, introducing crystallographic defects and CO groups. This physical and chemical modification of CFs in CFRP resulted in good adhesion of the electrodeposited copper.

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.

Assessment of the joint configuration and welding parameters for the dissimilar joining of AISI 304 L and AISI 410S stainless steels by friction stir welding

Assessment of the joint configuration and welding parameters for the dissimilar joining of AISI 304 L and AISI 410S stainless steels by friction stir welding

Mechanical response and microstructural evolution of a composite joint fabricated by green laser dissimilar welding of VCoNi medium entropy alloy and 17-4PH stainless steel

In engineering structures, the application of advanced alloys, such as the VCoNi medium-entropy alloy (VCoNi-MEA), with remarkable tensile strength (> 1 GPa) and superior ductility necessitates the employment of dissimilar joints. This study pioneers the dissimilar joining of VCoNi-MEA and 17–4 precipitation hardening stainless steel (17–4PH STS) using state-of-the-art green laser beam welding (LBW). To evaluate and optimize the experimental parameters, two welding speeds (200 and 300 mm/s) along with post-weld heat treatment (PWHT) were incorporated. High-quality welded joints with a single-phase face-centered cubic (FCC) structure in the fusion zone (FZ), minimal precipitates (< 1.6 %), and no visible cracks were successfully created. The LBW process demonstrated effective low-heat input characteristics, evident from a considerably narrow heat-affected zone (HAZ). Control over FZ width and grain size was achieved, measuring 600 and 112 μm at low welding speed and 250 and 49 μm at high welding speed, respectively, significantly lower than previous studies. A remarkably high yield strength (YS) of ∼620 MPa and ultimate tensile strength (UTS) up to 845 MPa were observed in the as-welded conditions, improving to ∼645 and 875 MPa, respectively, after PWHT. This enhancement in mechanical properties is primarily attributed to lattice friction induced by V addition. PWHT also improved joint ductility, increasing from 3.5 % to 8.6 % (low-speed) and from 6.3 % to 9.2 % (high-speed). The reduction in crystallographic orientation achieved using a higher welding speed and PWHT emerged as a major reason for improved mechanical properties. Slip-based deformation mechanisms dominated across all conditions, featuring crystallographically aligned slip bands. Interactions between existing and additional slip bands formed a dense dislocation network crucial for enhanced elongation after PWHT. Thermodynamic parameters elucidating phase stability in the observed FZs and contributions to superior YS were calculated and comprehensively discussed.

Study on Intermetallic Compound (IMC) in dissimilar joining of steel and aluminum (Fe-Al) – a review paper

Study on Intermetallic Compound (IMC) in dissimilar joining of steel and aluminum (Fe-Al) – a review paper

Ti/Mg dissimilar joining by eutectic-melting-induced liquid metal dealloying

Ti and Mg alloys, which have thermodynamically immiscible main components, have been chemically joined in previous work using a third element with high affinity for both elements. However, this strategy is challenging in precisely controlling brittle intermetallic compounds formed at a joint interface. In this study, we mechanically joined pure Ti and pure Mg without brittle layers by forming bicontinuous microstructure, 3D entanglement of immiscible phases, at the joint interface. We butt-joined pure Mg and Ti–Cu alloy interlayer, which we pre-diffusion bonded to the pure Ti and heated at 813 K and 20 MPa for 5 min. At the joint interface, Cu and Mg eutectic melted, which induced liquid metal dealloying of the interlayer. The entire Ti–Cu interlayer is dealloyed, and a byproduct (Mg–Cu phase) is removed by pressurization during melting. These brittle layer removal processes left only α-Ti/Mg–Cu phase bicontinuous microstructure at the joint interface, improving the joint strength. Ti/Mg joints fractured at the Mg base metal at ca. 90 MPa by tensile tests. The findings of this study provide the basis for achieving immiscible alloy joining, for which effective joining methods have not yet been established.

Numerical and experimental studies on dissimilar joining of Hastelloy C-276 and SS-316L using microwave hybrid heating at 2.45 GHz

Dissimilar joints of SS-316L and C-276 (Hastelloy) were developed using C-276 powder with microwave exposure 600 s in microwave applicator (2.45 GHz, 900 W). A multi-physics model was validated with experimental studies and simulation were carried out to analyse the microwave-joint interaction characteristics. The simulation results showed that a concentrated electric field (5.86 × 104 V/m) and higher resistive losses (3.07 × 107 W/m3) at the joint region facilitated rapid heat generation locally. Microstructural characterization of the joint revealed the formation of cellular grains such as Fe-Ni intermetallic phases with Mo, Cr and W-carbides along the grain boundaries. Joints exhibited average microhardness of 290 HV, and tensile strength of 425 ± 10 MPa and 14% elongation with failure due to both ductile and brittle fracture modes.

Dissimilar joining of AZ31B and Ti–6Al–4V sheets in lap joint using cold metal transfer welding

Ti–6Al–4V and AZ31B alloy sheets were joined in lap joint configuration using cold metal transfer welding with a synergic power source. The torch angle was kept approximately 45° away from the top plate. Wire feed speeds (WFSs) have been varied from 3.0 m/min to 7.0 m/min. Cold metal transfer welding results in good deposition of weld metal at higher WFSs but at the cost of poor bonding and defects. Joints of the best qualities were fabricated at a WFS of 3.0 m/min and a welding speed of 0.6 m/min. The torch angle assisted in the proper deposition of AZ31B weld metal with a good bond between weld metal and Ti–6Al–4V base metal. Microstructural analysis confirms the joint interface integrity by revealing the absence of defects. Also, there is a significant variation among the grain morphology of weld region, transition zone and base metal. The presence of several oxides (MgO4, Al2O3, etc.) and intermetallics (Mg17Al12, Mg7Zn3, AlMg4Zn11, etc.) is indicated by metallurgical analyses. Tensile-shear tests revealed that the joints could sustain the maximum load of 1871 N. Fractography reveals the mixed mode of fracture containing majority brittle, and a ductile failure at a few locations. The unusual fracture at a few locations indicates the presence of oxides in these regions.

An investigation on tensile shear strength of CMT spot weld-brazing of 5052 aluminium alloy and SS 400 galvanized steel

The main purpose of the research is to investigate the effects of spot weld-brazing variables, such as cold metal transfer (CMT) modes and current, on the tensile shear strength of 5052 aluminium alloy for dissimilar joining to SS400 galvanized steel.The method employed in the study was a 3k full factorial design with three replications. Analysis of variance (ANOVA) techniques were employed to identify the variables that influenced the responses of interest. The response optimiser method displayed which factors affected the variables and their impact on strength. In addition, the response optimiser method was employed to find which factors produced the best value for the response variable. A mathematical model was developed to predict the strength of the joints. An optical microscope (OM) and scanning electron microscope (SEM) were also employed to confirm the microstructure. Energy dispersive spectroscopy (EDS) was used to determine the chemical composition of the microstructure.The strength of the weld-brazing joints was affected by the modes and currents used in the joining process. The weld-brazing mode selection was found to have an impact on strength. The synergic mode was shown to have a strength greater than the CMT pulse and pulse synergic modes. The excess or little weld-brazing current was shown to be unsuitable for the joint. The maximum tensile shear strength value was obtained in the synergic mode with a current of 110 A. The resulting prediction model was evaluated with the newly collected experimental data, and the average per cent error was estimated to be 2.07%. In addition, the reaction layer at the aluminium alloy and steel interface was composed of a Fe(Al, Si)3 phase. The optimal conditions for the spot weld-brazing activities resulted in a larger fracture area, a small contact angle, and excellent weld bead geometry.The prediction accuracy of the model appeared satisfactory. However, the altered chemical composition of the filler metals and substrate materials could impact the findings. It is recommended that the electrical signal waveform be studied during spot weld-brazing, as well as the characteristics of other material joints with various other parameters.The weld-brazing mode and current had no significant effect on the type of interface layer of the joints.It is highly possible that the CMT spot weld-brazing technique could be applied to join other dissimilar materials in order to reduce the joining time, but the filler metal chosen must be appropriate.

Ultrasonic welding of Cork Wood/PLA composites: effect of welding factors on lap shear strength performance

Ultrasonic welding of Cork Wood/PLA composites: effect of welding factors on lap shear strength performance