3D printing, unlike other manufacturing processes, being an additive process has emerged as a viable technology for the production of engineering components. The aspects associated with 3D printing such as less material wastage, ease of manufacturing, less human involvement, very less post processing and energy efficiency makes the process sustainable for industrial use. The paper discusses numerous 3D printing processes, their advantages and disadvantages. A comprehensive description of different materials compatible for each type of 3D printing process is presented. The paper also presents the various application areas of each type of process. A dedicated section on industry 4.0 has also been included. The literature studied revealed that although the field of 3D printing has evolved to a great extent, there are still issues that need to be addressed such as material incompatibility and the cost of the materials. Future research could be undertaken to develop and modify the processes to suit a broad range of materials. To broaden the range of applications for 3D printed parts, more focus needs to be laid on developing cost effective printer technologies and materials compatible for these printers.

3D printing – A review of processes, materials and applications in industry 4.0

The automotive lightweighting trends, being driven by sustainability, cost, and performance, that create the enormous demand for lightweight materials and design concepts, are assessed as a part of the circular economy solutions in modern mobility and transportation. The current strategies that aim beyond the basic weight reduction and cover also the structural efficiency as well as the economic and environmental impact are explained with an essence of guidelines for materials selection with an eco-friendly approach, substitution rules, and a paradigm of the multi-material design. Particular attention is paid to the metallic alloys sector and progress in global R&D activities that cover the “lightweight steel”, conventional aluminum, and magnesium alloys, together with well-established technologies of components manufacturing and future-oriented solutions, and with both adjusting to a transition from internal combustion engines to electric vehicles. Moreover, opportunities and challenges that the lightweighting creates are discussed with strategies of achieving its goals through structural engineering, including the metal-matrix composites, laminates, sandwich structures, and bionic-inspired archetypes. The profound role of the aerospace and car-racing industries is emphasized as the key drivers of lightweighting in mainstream automotive vehicles.

Current Trends in Automotive Lightweighting Strategies and Materials

4D printing of shape memory polymer composites: A review on fabrication techniques, applications, and future perspectives

Additive manufacturing (AM) as a disruptive technology has received much attention in recent years. In practice, however, much effort is focused on the AM of polymers. It is comparatively more expensive and more challenging to additively manufacture metallic parts due to their high temperature, the cost of producing powders, and capital outlays for metal additive manufacturing equipment. The main technology currently used by numerous companies in the aerospace and biomedical sectors to fabricate metallic parts is powder bed technology, in which either electron or laser beams are used to melt and fuse the powder particles line by line to make a three-dimensional part. Since this technology is new and also sought by manufacturers, many scientific questions have arisen that need to be answered. This manuscript gives an introduction to the technology and common materials and applications. Furthermore, the microstructure and quality of parts made using powder bed technology for several materials that are commonly fabricated using this technology are reviewed and the effects of several process parameters investigated in the literature are examined. New advances in fabricating highly conductive metals such as copper and aluminum are discussed and potential for future improvements is explored.

Review of Powder Bed Fusion Additive Manufacturing for Metals

On the thermal buckling and postbuckling responses of temperature-dependent graphene platelets reinforced porous nanocomposite beams

Additive manufacturing (AM), also known as three-dimensional (3D) printing, has boomed over the last 30 years, and its use has accelerated during the last 5 years AM is a materials-oriented manufacturing technology, and printing resolution versus printing scalability/speed trade-off exists among various types of materials, including polymers, metals, ceramics, glasses, and composite materials Four-dimensional (4D) printing, together with versatile transformation systems, drives researchers to achieve and utilize high dimensional AM Multiple perspectives of the AM of structural materials have been raised and illustrated in this review, including multi-material AM (MMa-AM), multi-modulus AM (MMo-AM), multi-scale AM (MSc-AM), multi-system AM (MSy-AM), multi-dimensional AM (MD-AM), and multi-function AM (MF-AM) The rapid and tremendous development of AM materials and methods offers great potential for structural applications, such as in the aerospace field, the biomedical field, electronic devices, nuclear industry, flexible and wearable devices, soft sensors, actuators, and robotics, jewelry and art decorations, land transportation, underwater devices, and porous structures

Additive manufacturing of structural materials

Achieving high strength, deformability and toughness in polymers is important for practical industrial applications. This has remained challenging because of the mutually opposing effects of improvements to each of these properties. Here, a self-assembling nacre-like polymer composite is designed to achieve extremely tough with increasing strength. This special design significantly improved polymer's mechanical properties, including an ultra-high fracture strain of 1180%, a tensile strength of 55.4 MPa and a toughness of 506.9 MJ/m3, which far exceed the highest values previously reported for polymer composites. This excellent combination of properties can be attributed to a novel toughening mechanism, achieved by the synergy of the domain-limiting effect of metallic glass fragments with the strain-gradient-induced orientation and crystallisation within the polymer during stretching. Our approach opens a promising avenue for designing robust polymer materials in armour and aerospace engineering for a range of innovative applications. 

Self-assembling Nacre-like high-strength and extremely tough polymer composites with new toughening mechanism

Abstract Al–Cu alloy and Al–Cu–Y alloy deposits were formed by wire arc additive manufacturing (WAAM). Through metallography, SEM, EDS and tensile test in high temperature, the microstructure and mechanical properties in high temperature of the alloy accumulator were investigated. So as to investigate the effect of Y on the high temperature structure and properties of Al–Cu alloy deposits, the deposits were kept at 200 °C for 30 min. The results show that the addition of Y to the WAAM Al–Cu alloy deposit can significantly refine grain size, change the growth direction of the primary θ phase, increase the size of primary θ phase. More undissolved θ phases were nailed to the grain boundary after solution treatment, improved the yield strength of the accumulation. The addition of Y to Al–Cu alloy has no effect on strengthening phases in T6 state and the transformation of θ' strengthening phase at high temperature.

Xu Wang

Papers

Additive manufacturing of structural materials

Self-assembling Nacre-like high-strength and extremely tough polymer composites with new toughening mechanism

Effect of Y on microstructure and high temperature properties of wire-arc-additive-manufactured Al–Cu alloy deposits