Joining Of Materials Research Articles

A review on recent development in aluminium-copper friction stir welding

Aluminium (Al) and copper (Cu) are widely employed in the industry due to their significant corrosion resistance and electrical conductive properties. The simultaneous requirement of different special properties has increased the trend of joining of Al and Cu. The joining of dissimilar materials has arisen as a new challenge in the research field in the past decade. Friction stir welding (FSW) is a very worthy process to join metals that aren't the same. This article delves into the intricacies of FSW to join compatible metals such as Al and Cu. The various parameters of FSW, namely tool design, tool pin offset, rotation speed, welding speed, tilt angle, and different types of welding joints, are highlighted in this article. It also goes through the different types of defects, microstructures, and intermetallic compounds (IMCs) that are formed during Al-Cu FSW. The electrical behavior and corrosion behavior of the weld zone in Al-Cu FSWed joints were also reviewed. Role of interlayer in some emphasis was also given to form effective joints.

Investigations of Microstructure and Mechanical Properties of Lap Jointed Dissimilar Metals by Friction Stir Spot Welding Process

The joining of different materials is required for industrial application to utilize the hydride structures with attractive advantages such as superior strength to weight ratio, low cost, high tensile strength and less weight of the component. Specifically, Al-Cu composite material is widely used in foil conductors of a transformer, electrical connectors, foil windings in capacitors and tubes in heat exchangers. However, joining or spot welding the Al parts to Cu parts are significant challenge owing to variation in mechanical properties and chemical compositions of joining materials. In this present research work, the friction stir spot welded process (FSSWP) is carried out to join the Al and Cu materials. Further, microstructure and mechanical properties of friction stir spot welded specimens (FSSW) are studied at different tool rotational speeds likely from 1000rpm to 1500rpm. The microstructural study is carried out using scanning electron microscope images at the interface and overall welded region. The tensile strength of both single and double spot-welded specimens is analyzed using a universal tensile test machine. The output of this study states that the optimal tool rotational speed is 1500rpm for both single and double spot-welded specimens. Moreover, the double spot-welded specimen exhibits more tensile with a crack-free spot-welded surface than that of the single spot-welded specimen. The tensile strength double spot-welded specimen has a 6.8% higher strength than that of a single spot-welded specimen. Based on the present study, it is concluded that the double spot-welded specimen can be used for different industrial applications to replace Cu material with this Al-Cu material that gives added advantages to those components.

Research Progress of Interfacial Design between Thermoelectric Materials and Electrode Materials.

Intensive efforts have been conducted to realize the reliable interfacial joining of thermoelectric materials and electrode materials with low interfacial contact resistance, which is an essential step to make thermoelectric materials into thermoelectric devices for industrial application. In this review, the roles of structural integrity, interdiffusion, and contact resistance in long-term reliabilities of thermoelectric modules are outlined first. Then interfacial reactions of near-room-temperature Bi2Te3-based thermoelectric materials and various electrode materials are reviewed comprehensively. We also summarized the joining behavior of the mid-temperature PbTe-based thermoelectric materials and commonly used electrode materials. Subsequently, for other thermoelectric materials systems, i.e., SiGe, CoSb3, and Mg3Sb2, previous attempts to join with some electrode materials are also recapitulated. Finally, some future prospects to further improve the joint reliability in thermoelectric device manufacturing are proposed. We believe that this review will provide guidance for preparing thermoelectric devices and optimizing thermoelectric device design.

Optimization of friction stir welding parameters for improved ultimate tensile strength

Friction stir welding process is a solid-state welding process, use non-consumable rotating tool to produce joints, it has been widely used for joining of similar and dissimilar materials in automobile, aerospace, railway and other industries. In the present work, Taguchi methodology based on L16 orthogonal array has been used to investigate the influence of rotational speed (rpm), welding speed (mm/min), axial force and water head (mm) on the UTS (Ultimate Tensile Strength) of the weld joints during the FSW (friction stir Welding) of AA 7039 alloy plates. The results shows that rotational speed is the most significant FSW condition that affect the UTS followed by welding speed, water head and axial load. Also, for the developed model, R2 value has been achieved as 0.999 and adjusted R2 value is equal to 0.997, which indicate excellent agreement between experimental and predicted values.

3D Printing: A Promising Revolutionary Technology in Pharmaceutical Drug Development and Health Car

The three-dimensional (3D) printing technique is an emerging paradigm shift in the field of drug manufacturing. It also proved to be a promising technology with respect to the pharmaceutical, clinical medicine, and regulatory sciences. It is a modern additive manufacturing technology in which digital information is used to produce a physical model. Unlike other subtractive and formative manufacturing processes which involve removing sections of material by machining or by cutting it away, in 3D printing technology objects are prepared from 3D model data in the process of joining materials layer by layer. In drug therapy, 3D printing has abundant opportunities for rapid preparation of multifunctional customized drug delivery systems with improved drug release features, flexible and personalized dosage forms, implants matching specific patient anatomical needs as well as cell-based materials for regenerative drug therapy and prosthesis. The 3D printing methods have gained vast importance in the field of pharmaceutical and medical applications. It is an interdisciplinary approach with the aim of exploring newer drug-delivery systems. 3D printing could also become a part of the drug production line in the pharmaceutical industry which tends to move towards personalized medicine along with mass manufacture. Presently 3D printing technology is broadly investigated in the field of drug delivery after the approval of the first 3D printed tablet containing an antiepileptic drug, levetiracetam under the trade name of Spritam® by Aprecia Pharmaceuticals in 2015. The present review recapitulates the novel applications of 3D printing technology in the field of pharmaceutical drug development and health care. It also reviews the working principle of various techniques of 3D printing along with their advantages and disadvantages.

Influence of different surface conditions on mechanical properties during ultrasonic welding of aluminum wire strands and copper terminals

Ultrasonic metal welding (USMW) has become considerable attention in terms of its suitable applications compared to conventional fusion welding techniques. The main advantage of USMW results from the comparatively low process times and joining temperatures below the melting point. Thus, USMW is particularly used for the joining of dissimilar material combinations, e.g., aluminum and copper (Al/Cu), in battery cell production or wiring harness applications. However, process fluctuations in USMW of Al/Cu joints can occur due to varying surface conditions of the joining materials. Therefore, this study investigated different surface conditions of copper terminals and their effects on mechanical properties. At first, three different surface conditions were generated, respectively: surface cleaning (sulfuric acid and ethanol), structuring process by laser, and structuring process by milling. These modifications are compared with the terminals in the initial state (contaminated). The characterization of the terminal surfaces was carried out with 3-D laser scanning microscopy as well as light microscopy. The mechanical conditions were examined with shear tensile tests. The tensile tests showed a significant influence of the surface condition on the resulting failure loads compared to the initial state. The highest failure loads could be achieved with the structured terminals (+ 48%), whereas contaminated terminals and terminals with notches exhibited comparatively poor failure loads (− 28%). This can be explained by varying interface formations between the terminal and the wire, which was detected by metallography and SEM analysis. Furthermore, it was figured out that the interface between aluminum and copper exhibits a firm and formed closure bond and hence increased failure loads for laser-structured terminals. Additional investigations by SEM revealed no detectable occurrence of intermetallic phases.

Application of microwave in manufacturing technology: A review

In todays world due to wide experimentation of materials and wider application in various field and with introduction of reduced production or manufacturing costs, and processing lead times, newly developed processing technology is what is required with these advantages. The newly developed processing techniques should be such that it should be widely acceptable for all types of materials including metals, non-ferrous metals, non-metals etc. Such processing methods are many but microwave processing is one of the fastest and latest emerging manufacturing technology that has found new application in material joining, casting, heat treatment, cladding, sintering, machining and drilling. In comparison to other conventional processes, microwave processing of materials not only enhances the mechanical properties but also redues the defects and has certain economical advantage in power and time savings. In comparison to conventional processes, microwave processing due to hybrid and selective heating, the parts produced has more uniform, axial, cellular and homogeneous type of structure is obtained. It has found application in not only in food processing industry but wide application has been found in manufacturing industry. Though other processes are available in the industries like electric furnace and ohmic resistance heating but the microwave due to its properties like penetration radiation, controllable electric field distribution, rapid heating, selective heat, self limit reactions with advantage of lower environmental impact has been extensively used for industrial and material processing applications. This work describes the review focusses on technological advancement of microwave processing of materials and their application in manufacturing applications in industries.

Fatigue behaviour of multi-spot joints of 2024-T3 aluminium sheets obtained by refill Friction Stir Spot Welding with polysulfide sealant

The aeronautical industry is looking with interest at friction-based welding for many years due to weight-saving capacities, where fusion-based welding problems can be avoided, allowing also the joining of materials considered complicated to weld with other technologies. Refill Friction Stir Spot Welding (refill FSSW) is a solid-state joining process that shows great potential to be a substitute for single-point joining processes like riveting. The main objective of this study is to investigate the mechanical behaviour of multi-spot joints of AA 2024-T3 obtained by refill FSSW with the addition of a sealant commonly used in riveted joints by the aviation industry. A fatigue test campaign was carried out on the joints with and without sealant to evaluate the possible synergy between the refill FSSW and sealant. The fatigue data obtained are statistically analyzed and compared. According to the comprehensive study including macro- and micro-structure, deformation strain field, residual stress distribution as well as the fatigue crack growth behaviour, the underlying history of multi-spot joints fatigue damage is revealed. The overall results prove that producing lap-joints by refill FSSW with sealant improves considerably the fatigue performance.

A Literature Survey on Electrical-Current-Assisted Friction Stir Welding

Electrical-current-assisted friction stir welding (EA-FSW) is a procedure developed for the joining of similar and dissimilar materials. EA-FSW is a newly invented solid-state process to increase welded components’ efficacy in various applications, such as marine structures. EA-FSW joints have investigated the dissimilar joints on aluminum–magnesium, aluminum–steel, and polymer-to-steel. Similar joints have been performed on aluminum, magnesium, and steel. The main parameters that affect the temperature of the nugget in EA-FSW are electrical current and tool rotational velocity. This review paper presents the fundamental principle of EA-FSW, its processes mechanism, and various types of tools, and discusses the different joints that EA-FSW welded. The effect of electrical current on the quality of similar and dissimilar joints is discussed. The simulation process and detailed modeling of the EA-FSW process are discussed in the last section.

Joining of SiC ceramics by combining NITE-SiC interlayer and its thickness control

Combined with the thickness control of interlayers (∼10 µm and ∼60 µm), SiC nano-powders with Al2O3-Y2O3-MgO-CaO additive (NITE-SiC) were used as the joining materials to achieve the low-temperature joining of SiC ceramics. Some residual pores were observed in the interlayer with a thickness of ∼60 µm after joining at 1650 ℃, and the shear strength of SiC joints measured was 39.3 ± 5.5 MPa. Observations showed the fracture of joints occurred at the interlayer. When the thickness of the interlayer decreased to ∼10 µm, no cracks or porosity were observed at the interface region after joining at 1650 ℃. The shear strength of SiC joints increased to 69.5 ± 8.9 MPa, and the fracture originated from the matrix. The results demonstrated using NITE-SiC with Al2O3-Y2O3-MgO-CaO additive as the joining layer and reducing the thickness of the interlayer could lower the joining temperature and significantly improve the mechanical strength of joints.

Experimental and Numerical Testing of the Brazing of Engineering Ceramics Made of Alumina to SS 304

Material scientists have always faced a significant obstacle in the process of joining materials that are distinct from one another. The main aim of this research is to join stainless steel with alumina under pressure. The ceramic and stainless steel SS 304 were joined in this work by brazing with a torch and furnace. The study focused on a ceramic-to-stainless steel joint: a stainless steel 30 mm stripe that was brazed to alumina using the same brazing alloy and alumina to themselves. The joints were evaluated using numerical analysis, and the module was run by Ansys 18.2 in Solidworks 2017. The tensile strength of the experimental work reached 62 MPa during slow cooling with pressurized air at the furnace, as shown by the numerical analysis result. This is lower than the fracture of the ceramic material alumina.The Tensile Stress at 65.3MPa in the numerical analysis corresponds nearly exactly to the experimental work.

Pulsed laser welding of macroscopic 3D graphene materials.

Welding is a key missing manufacturing technique in graphene science. Due to the infusibility and insolubility, reliable welding of macroscopic graphene materials is impossible using current diffusion-bonding methods. This work reports a pulsed laser welding (PLW) strategy allowing for directly and rapidly joining macroscopic 3D porous graphene materials under ambient conditions. Central to the concept is introducing a laser-induced graphene solder converted from a designed unique precursor to promote joining. The solder shows an electrical conductivity of 6700 S m-1 and a mechanical strength of 7.3 MPa, over those of most previously reported porous graphene materials. Additionally, the PLW technique enables the formation of high-quality welded junctions, ensuring the structural integrity of weldments. The welding mechanism is further revealed, and two types of connections exist between solder and base structures, i.e., intermolecular force and covalent bonding. Finally, an array of complex 3D graphene architectures, including lateral heterostructures, Janus structures, and 3D patterned geometries, are fabricated through material joining, highlighting the potential of PLW to be a versatile approach for multi-level assembly and heterogeneous integration. This work brings graphene into the laser welding club and paves the way for the future exploration of the exciting opportunities inherent in material integration and repair.

Ultrasonic spot welding for joining dissimilar metals and composite materials

Ultrasonic spot welding (USW) is a solid joining technique widely known for the joining of metals and composite materials. However, joining dissimilar metals using USW introduces voids, swirl-like structures, and poor intermetallic compounds around weld interfaces. This paper examines the current state of USW for joining dissimilar metals and composite materials. Several critical issues were also discovered including technique, defect, stress distribution, and macrostructure. This review summarized the understanding of the fundamental phenomena involved in weld formation during USW of dissimilar material. Finally, the way forward in the field of spot welding is also presented.

The role of interface in joining of 316 L stainless steel and polylactic acid by additive manufacturing

Joining of dissimilar materials is of high technological interest, given the emerging multi-material additive manufacturing. Especially, joining of metals and polymers is challenging given the major differences of the melting point, thermal expansion, and shrinkage. New, easy-to-manufacture interface geometries are proposed for 316 L stainless steel produced by laser powder bed fusion and polylactic acid by fused filament fabrication. The role of roughness, interface geometry, polymer integration in the metallic interface geometry and residual stresses is investigated experimentally in tension and by finite element analysis. Appropriate heating and design of the interface geometry prove to offer an improved interface strength.

Strength of dissimilar adhesively bonded DCB joints and its connection with the failure pressure of composite repair systems

The application of adhesively bonded joints in petroleum industry over other traditional joining methods has increased significantly in recent years mainly because of the potential for light weight structures, fast repairing systems and low temperature applications. The principal benefits are design flexibility and joining of dissimilar materials. Therefore, accurate analysis and study about the mechanical behavior of dissimilar materials joints are fundamentally required since composite materials are widely used as repair systems for metallic pipelines with localized flaws or damage that prejudice the serviceability. Experimental analyses were performed on dissimilar adhesively bonded DCB joints, similar to a composite repair applied to a pipeline, to investigate the design factors that affect the joint behavior. This study shows that the critical energy release rate obtained in dissimilar DCB joints tests can be correlated with the one obtained in hydrostatic tests performed in pipelines with though-wall defects repaired with composite sleeves. It is proposed an approximated theoretical framework that allows obtaining an estimate of critical fracture parameters that arise in composite repair standards only using simpler and less expensive DCB tests in the place o hydrostatic test.

Mechanical joining of high-strength multi-material systems − trends and innovations

In conjunction with mechanical joining processes. Mechanical joining processes play a key role for the realization of multi-material lightweight structures, which are essential with regard to environmental protection. However, joining of dissimilar high-strength materials is challenging due to the varying properties of the joining partners and due to their high flow stresses and often limited ductility. Thus, the evolution of established processes as well as the development of innovative and highly productive joining technologies are necessary. Requirements for a highly volatile production environment are versatility, flexibility, resilience and robustness. Within this contribution, current trends and innovations related to selected mechanical joining processes for enabling the material mix are outlined in order to point out opportunities to address these requirements in the future. In this context, joining using cold formed pin structures is presented as a promising approach for connecting dissimilar materials like metals to fibre-reinforced plastics. Furthermore, it is shown how the shear-clinching technology can be combined with a process-adapted application of locally limited heat treatment in order to promote the joinability and control the material flow during joining. A novel approach for reducing process forces and expanding process windows is the use of ultrasonic assistance for mechanical joining operations, which is demonstrated by the example of a nut staking process with superimposed high frequency oscillation. As concerns the widely used self-piercing riveting technique, current research activities relate not only to the further development of the joining process itself, for example by combining self-piercing riveting and tumbling, but also to the use of new rivet materials like high strain hardening stainless steels. In addition, the evolution towards mechanical joining 4.0 against the background of data-based process control in conjunction with of mechanical joining processes is also subject of the considerations.

Tehnologija proizvodnje 3D štampanih modela na različitim materijalima korišćenjem procesa fuzionog taloženja materijala

The joining of thermoplastic and textile materials is gaining more and more importance today. New combinations of materials and new structures that change fashion trends are obtained. The paper presents the technology of joining thermoplastic materials with different fabrics. For example, the realization of a button on textiles and the description of 3D printing were taken. This pioneering venture describes the technology, fabric model-making process, and materials melting bond analysis. Unfortunately, available thermoplastic materials have many limitations regarding durability, aging, and service life according to the defined requirements. The idea of this paper is the application of 3D printing in the fashion industry as an emerging topic for discussion. The experimental part of this investigation will provide a new guideline for designers of PLA/ABS printing elements on textile substrates and possibility for application in modern textile design.

Numerical Simulation of Mechanical Joining of Three DP600 and DC06 Steel Sheets

There are many reasons to utilize various grades of steel in car body production. Automotive producers tend to choose steels with great formability and the capacity to absorb impact energy. The dominant method used for joining car body sheets has for many years been resistance spot welding, but the use of various steel sheets leads to research into alternative joining methods. Mechanical joining - clinching, is the innovative method to join these materials. Numerical simulation tools are used to optimize the joining of materials. Simufact Forming software was used to analyse the clinching joining of three sheets of material DP600 and DC06. According to the axisymmetric character of the mechanical joining process, the simulation was stream-lined to a 2D representation. The results of the simulation of the mechanical joining process were compared with the real samples prepared for metallographic observation.

Implementing digital twinning in an additive manufacturing process chain

Additive manufacturing (AM) is defined as the process of joining materials layer by layer to produce a part. The Centre for Rapid Prototyping and Manufacturing (CRPM) of the Central University of Technology, Free State has successfully established an AM process chain to produce qualified medical implants. The process chain complies with the international standards ISO 13485:2016 and ISO 14971:2012, which certify the repeatability and reliability of processes. Despite the significant achievements CRPM has obtained in medical applications, efficiency in some areas can be improved through digital twinning approaches. The digital twin has comprehensive capabilities and allows real-time monitoring that can be used to improve different phases of AM processes. In this study, areas that need further improvement in the process chain, such as management information that flows between different users and processes for design and setting up AM machines, will be discussed. The study will further indicate how these areas can benefit from available advanced technologies such as augmented reality (AR) technology and digital twin data management. Further implementation of this approach is expected to confirm the potential of easy self-learning approaches and managing data more effectively for improving the AM process chain.

Dissimilar material joining of Al alloy and carbon steel by center-driven double-sided linear friction welding

Dissimilar material joining of Al alloy and carbon steel by center-driven double-sided linear friction welding