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An ongoing revolution in the development and implementation of new materials has placed new demands on the ability to join these materials into devices, parts and components, and devices, parts and components into packages, assemblies and structures for both electrical and mechanical applications. Looks at the past successes and shortcomings of traditional joining technologies. Presents some obvious and some not‐so‐obvious directions as one attempt at prognostication of the needs for new joining technologies for the forthcoming new century.

From when we, as humans, first lashed a pointed stone to a split straight stick to make a more effective spear for hunting to now when we fasten and bond ablative ceramic tiles to the frail metal skin of the Space Shuttle to allow safe re‐entry from manned excursions into space, joining has been a pragmatic, albeit critically important, fabrication process. As we move beyond the Industrial Age to the ages of Information Technology, Nanotechnology, and Biotechnology, joining must move from a secondary process for manufacturing objects or articles from pre‐synthesized and pre‐shaped materials to a primary process for combining materials into fundamental structures as these structures and even materials are being synthesized; where the boundary between the materials and the structure becomes blurred. This paper attempts to catch a glimpse of the future where joining comes of age to become an enabling technology practiced as much or more by technicians or physicians than as a trade practiced by helmeted welders or hard‐hatted riveters.

Joining, while first and foremost a pragmatic undertaking, concerned more with needs and results than with theory, will likely have to change with the dawn of the twenty‐first century to a true science. As materials become ever‐more sophisticated in their chemical composition, molecular morphology, micro‐ and nano‐structure, and macro‐structural arrangement to provide ever‐better functionally specific properties, a more complete and precise understanding of how such materials can be joined for optimal effectiveness and efficiency will become essential. Traditional options for joining will surely evolve – sometimes to provide unimagined capabilities. But, in addition, totally new methods will almost certainly emerge as evolution of materials gives way to revolution to meet unimagined new designs and design demands. This paper takes a glance at the past and a hard look at the present in the hope of catching a glimpse of the future.

The purpose of this paper is to based upon the joining and characterization (mechanical and metallurgical) of ferritic stainless steel (SS)-430 using a microwave hybrid heating (MHH) phenomenon.

The preliminary experiments were conducted using nickel-based powder as interface material using a domestic microwave oven at a frequency of 2.45 GHz and 900 W power for 720 s. The processed joint was metallurgically characterized by means of X-ray diffraction, Energy-dispersive X-ray spectroscopy and Field emission scanning electron microscopy. Mechanical characterization was done by means of tensile and Vickers’ microhardness testing to check the hardness and strength of the joint.

The metallurgical study revealed that the microstructure and formation of numerous phases of Fe₂Si₃ accompanied by chromium and nickel carbides. The average hardness of 359 Hv at the center of the joint and 637 Hv around the boundaries of the joint was observed. The tensile strength of the joint was observed to 471 MPa with an elongation of 9.02%. The worn surface of the joint signifies the presence of plastic deformation and it was limited due to the presence of harder phases such as Ni₃Si and Ni₃C.

The concept of microwave joining of metals is a very challenging task as the temperature can not be controlled in the inert atmosphere of the microwave. It has been also observed that at certain elevated temperatures, the material starts absorbing the microwaves; which is unknown. So, a more intensive study is required to overcome these kinds of limitations.

MHH technique can be used to process different materials such as ceramics, composites and polymers. SS-430 joined by microwave heating is highly corrosion resistive and has wide applications in refrigerators cabinet panels, dishwasher linings, chimney liners, lashing wires, etc.

As of the author’s best knowledge, no work has been reported on the joining of SS-430 which has huge potential in the industries. Also, no work has been reported on the characterization of microwave joined SS-430.

The purpose of this paper is to join an anodized aluminium alloy AA6061 sheet with high-density polyethylene (HDPE) using friction spot process.

The surface of AA6061 sheet was anodized to increase the pores’ size. A lap joint configuration was used to join the AA6061 with HDPE sheets by the friction spot process. The joining process was carried out using a rotating tool of different diameters: 14, 16 and 18 mm. Three tool-plunging depths were used – 0.1, 0.2 and 0.3 mm – with three values of the processing time – 20, 30 and 40 s. The joining process parameters were designed according to the Taguchi approach. Two sets of samples were joined: the as-received AA6061/HDPE and the anodized AA6061/HDPE.

Frictional heat melted the HDPE layers near the lap joint line and penetrated it through the surface pores of the AA6061 sheet via the applied pressure of the tool. The tool diameter exhibited higher effect on the joint strength than processing time and the tool-plunging depth. Specimens of highest and lowest tensile force were failed by necking the polymer side and shearing the polymer layers at the lap joint, respectively. Molten HDPE was mechanically interlocked into the pores of the anodized surface of AA6061 with an interface line of 18-m width.

For the first time, HDPE was joined with the anodized AA6061 by the friction spot process. The joint strength reached an ideal efficiency of 100 per cent.

The purpose of this paper is to join sheets of an aluminium alloy together with pre-holed carbon steel via friction spot technique.

An AISI 1006 steel sheet was a pre-holed with a 4.8 mm diameter and put under AA5052 sheet with a lap joint configuration. The joining process was carried out by extruding the aluminium through the steel hole using a rotating tool of 10 mm diameter. Furthermore, three process parameters (pre-heating time, rotating speed and plunging depth of the tool) with three values for each parameter were used to study their effects on the joints quality. In order to join samples, nine experiments were designed according to a Taguchi method. Shear strength, microstructure and X-ray diffraction tests of the joint were carried out.

The joining mechanism occurred by a mechanical interlock of the extruded aluminium with the inner surface of the steel hole. The tool plunging depth had a significant effect on the shear strength of the joint. The shear strength of two joints exceeded the shear strength of the wrought material (AA5052). All samples failed with two modes: pull-out and shearing of the extruded aluminium.

For the first time, the extrusion technique was used to join AA5052 sheet together with pre-holed carbon steel, with a perfect joint efficiency.

The purpose of this study is to present a comprehensive review of the fundamental concepts and terminologies pertaining to different types of aluminium metal matrix composites, their joining techniques and challenges, friction stir welding (FSW) process, post-welding characterizations and basic control theory of FSW, followed by the discussions on the research reports in these areas.

Joining of aluminium metal matrix composites (Al-MMC) poses many challenges. These materials have their demanding applications in versatile domains, and hence it is essential to understand their weldability and material characteristics. FSW is a feasible choice for joining of Al-MMC over the fusion welding because of the formation of narrow heat affected zone and minimizing the formation of intermetallic compounds at weld interface. The goal in FSW is to generate enough thermal energy by friction between the workpiece and rotating tool. Heat energy is generated by mechanical interaction because of the difference in velocity between the workpiece and rotating tool. In the present work, a detailed survey is done on the above topics and an organised conceptual context is presented. A complete discussion on significance of FSW process parameters, control schemes, parameter optimization and weld quality monitoring are presented, along with the analysis on relation between the interdependent parameters.

Results from the study present the research gaps in the FSW studies for joining of the aluminium-based metal matrix composites, and they highlight further scope of studies pertaining to this domain.

It is observed that the survey done on FSW of Al-MMCs and their control theory give an insight into the fundamental concepts pertaining to this research area to enhance interdisciplinary technology exploration.

The purpose of this paper is to compile a comprehensive status report on pipes/piping networks across different industrial sectors, along with specifications of materials and sizes, and showcase welding avenues. It further extends to highlight the promising friction stir welding as a single solid-state pipe welding procedure. This paper will enable all piping, welding and friction stir welding stakeholders to identify scope for their engagement in a single window.

The paper is a review paper, and it is mainly structured around sections on materials, sizes and standards for pipes in different sectors and the current welding practice for joining pipe and pipe connections; on the process and principle of friction stir welding (FSW) for pipes; identification of main welding process parameters for the FSW of pipes; effects of process parameters; and a well-carved-out concluding summary.

A well-carved-out concluding summary of extracts from thoroughly studied research is presented in a structured way in which the avenues for the engagement of FSW are identified.

The implications of the research are far-reaching. The FSW is currently expanding very fast in the welding of flat surfaces and has evolved into a vast number of variants because of its advantages and versatility. The application of FSW is coming up late but catching up fast, and as a late starter, the outcomes of such a review paper may support stake holders to expand the application of this process from pipe welding to pipe manufacturing, cladding and other high-end applications. Because the process is inherently inclined towards automation, its throughput rate is high and it does not need any consumables, the ultimate benefit can be passed on to the industry in terms of financial gains.

To the best of the authors’ knowledge, this is the only review exclusively for the friction stir welding of pipes with a well-organized piping specification detailed about industrial sectors. The current pipe welding practice in each sector has been presented, and the avenues for engaging FSW have been highlighted. The FSW pipe process parameters are characteristically distinguished from the conventional FSW, and the effects of the process parameters have been presented. The summary is concise yet comprehensive and organized in a structured manner.

Clinching is, due to its characteristics, a joining method with several advantages. The high joining forces, which require heavy process equipment are a major disadvantage. The Fraunhofer Institute has developed clinching methods which reduce the joining forces considerably to make clinching applicable for further developments and new application areas.