Additive manufacturing of cemented carbides: Differences between beam-based and sinter-based technologies

Microstructure and mechanical properties of WC–Co-based cemented carbide with bimodal WC grain size distribution

Additive Manufacturing (AM) is a well-known technology, first patented in 1984 by the French scientist Alain Le Mehaute [...]

This paper adopts area conversion method to measure the WC grain size manually, sets up a Fibonacci Sequence plane segmentation model based on the statistical data obtained, and studies the effect of the ratio of coarse WC grains to fine WC grains on dual grain structure cemented carbide. It is believed that when SWC (fine) / SWC (coarse) ratio is 0.382, theoretically speaking, the arrangement between WC grains is the tightest. Through investigating the effect of WC grain boundary fusion on its stacking density and contiguity, and the effect of the dissolution and precipitation of WC grains on SWC(fine) / SWC(coarse) ratio, and combining Li Guangyu’s random stacking structure of the cemented carbide theory, it expounds the formation mechanism of the dual grain structure cemented carbide—making a proper amount of fine WC grains fill in the gaps between coarse WC grains so as to increase the stacking density and contiguity of WC grains to the maximum degree, and to separate the accumulated Co-phase layer between coarse WC grains, so that the Co layer more evenly distributes among the fine WC grains.

Effect of carbon content on the properties of inhomogeneous cemented carbides with fine-grained structures produced via one-step transformation

Fabrication of dual-grain structure WC-Co cemented carbide by in-situ carbothermal reduction of WO3 and subsequent liquid sintering

Special Issue on Tribology of Additive Manufacturing

Characterization of Inconel 625 fabricated using powder-bed-based additive manufacturing technologies

Additive manufacturing (AM) technologies have gained considerable attention in recent years as an innovative method to produce high entropy alloy (HEA) components. The unique and excellent mechanical and environmental properties of HEAs can be used in various demanding applications, such as the aerospace and automotive industries. This review paper aims to inspect the status and prospects of research and development related to the production of HEAs by AM technologies. Several AM processes can be used to fabricate HEA components, mainly powder bed fusion (PBF), direct energy deposition (DED), material extrusion (ME), and binder jetting (BJ). PBF technologies, such as selective laser melting (SLM) and electron beam melting (EBM), have been widely used to produce HEA components with good dimensional accuracy and surface finish. DED techniques, such as blown powder deposition (BPD) and wire arc AM (WAAM), that have high deposition rates can be used to produce large, custom-made parts with relatively reduced surface finish quality. BJ and ME techniques can be used to produce green bodies that require subsequent sintering to obtain adequate density. The use of AM to produce HEA components provides the ability to make complex shapes and create composite materials with reinforced particles. However, the microstructure and mechanical properties of AM-produced HEAs can be significantly affected by the processing parameters and post-processing heat treatment, but overall, AM technology appears to be a promising approach for producing advanced HEA components with unique properties. This paper reviews the various technologies and associated aspects of AM for HEAs. The concluding remarks highlight the critical effect of the printing parameters in relation to the complex synthesis mechanism of HEA elements that is required to obtain adequate properties. In addition, the importance of using feedstock material in the form of mix elemental powder or wires rather than pre-alloyed substance is also emphasized in order that HEA components can be produced by AM processes at an affordable cost.

Significant contributions have been made in recent years to the development of Additive Manufacturing (AM) technology. Improvements in laser and electron beam-based AM equipment using powder injection, powder bed or wire feed systems have benefited from advances in software programs to convert complex CAD models into Digitally Manufactured parts. Wider acceptance of AM technology in, for example the aerospace industry, is driven by meeting stringent quality, schedule and cost requirements. These factors, in addition to the specific property requirements and level of part-family complexity, strongly influence the selection of the appropriate Additive Manufacturing process. This presentation will briefly review some of the factors and criteria that must be addressed to transition an “AM opportunity” into a viable business case. Introduction Additive Manufacturing (AM) may be defined as: a collective term for manufacturing technologies, which in an automated process produce 3-D objects, as a whole or in part, directly from 3-D CAD data, by the successive addition of materials without the use of specialized tooling. AM is a relatively new technology with a history spanning ~40 years. This is insignificant compared to “Subtractive” and “Formative” shaping. However, significant contributions have been made in recent years to the development of AM technology and the state-of-the-art is rapidly changing. Improvements in laser and electron beam-based AM equipment using powder injection, powder bed or wire feed systems have benefited from advances in software programs to convert complex CAD models into Digitally Manufactured, i. e., “e-manufactured” parts. Wider acceptance of AM technology use in, for example the aerospace industry, is driven by meeting stringent quality, schedule and cost requirements. These “business case” factors, in addition to the specific property requirements and level of part-family complexity, strongly influence the selection of the appropriate Additive Manufacturing process. Some AM processes are conducive to small, complex geometry, Free-FormFabrication (FFF) parts, having tight-tolerance Net-Shapes. Others, programmed via robotics/multi-axis machines, can span the part size range up to FFF larger parts or feature-additions. The surface finish on products from several AM processes is still Near-Net-Shape. An important goal is the minimization of any post-processing, such as machining or surface finishing, to achieve Net-Shape capability within the surface finish tolerances of the part design.

Binder jetting 3D printed cemented carbide: Mechanical and wear properties of medium and coarse grades

This study implements DC arc plasma treatment on WC–Co powder to suppress any relevant powder-derived defects toward realizing the fabrication of high-quality cemented carbide via additive manufacturing (AM). We achieved the optimum plasma processing conditions which suitably yielded WC powder having suppressed decarburized particles and reduced internal gaps. Moreover, the apparent density and flowability of the plasma-treated powder were improved relative to the raw powder. AM trials were then performed to verify the potentials of plasma-treated powder in a laser powder bed fusion (L-PBF). Plasma treatment improved the powder packing density and the surface roughness of the powder, therefore enhancing the thermal conductivity and reducing the heat accumulation in the powder bed layer. Subsequently, the formation of coarse WC grains along with the fine pores-containing brittle phase were suppressed as observed from the cross-sectional microstructure analysis, hence demonstrating the suitability of the said powder in the L-PBF AM process.

To review the current metal-based additive manufacturing (AM) technologies, namely powder bed fusion (PBF) technologies, and their current prosthodontic applications. The PBF technologies reviewed are selective laser sintering (SLS), selective laser melting (SLM), and electron beam melting (EBM). The literature on metal AM technologies was considered, and the AM procedures and their current applications in prosthodontics were collated and described. Published articles about AM metal in dental care were searched (MEDLINE, EMBASE, EBSCO, and Web of Science). All studies related to the description, analysis, and evaluation of prosthodontic applications using metal AM technologies. AM technologies are reliable for many applications in dentistry, including metal frameworks for removable partial dentures (RPDs), overdentures, tooth- and implant-supported fixed dental prostheses (FDPs), and metal frameworks for splinting implant impression abutments. However, further studies are needed in future to evaluate the accuracy, reproducibility, and clinical outcome throughout function of AM technologies.

This book chapter elaborates on different additive manufacturing (AM) processes of copper and copper alloys. The scope is to give the reader a basic understanding of the state-of-the-art of copper additive manufacturing by different AM technologies, such as laser powder bed fusion (LPBF), laser metal deposition (LMD), binder jetting (BJ), and metal-fused filament fabrication (M-FFF). Furthermore, we want the reader to be able to use this knowledge to find and assess potential use cases. Recently, with the commercial availability of green laser sources, the difficulties for laser processing of pure copper were overcome, which gave AM technologies, such as LPBF and LMD new momentum and increased interest. AM technologies involving a subsequent sintering step. They are relatively new and gained interest due to fast build-up rates (BJ) or ease of operation (M-FFF). We will cover important material-related properties of copper and its implications for manufacturing and application (e.g. absorption, sinterability, conductivity, and its dependency on impurities). Further, we address applications for AM copper, present the state-of-the-art for above mentioned AM technologies and share our own recent research in this field.

A thermal-initiated monomer binder enhancing green strength with low binder saturation for binder jetting additive manufacturing of cemented carbide

Beam shaping technology and its application in metal laser additive manufacturing: A review