Additive manufacturing of metals
TL;DR: In this paper, the authors describe the complex relationship between additive manufacturing processes, microstructure and resulting properties for metals, and typical microstructures for additively manufactured steel, aluminium and titanium are presented.
About: This article is published in Acta Materialia.The article was published on 2016-09-15. It has received 2837 citations till now. The article focuses on the topics: Aluminium.
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17 Sep 2017-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the authors examined changes in the microstructure and mechanical properties of AlSi10Mg alloy, initially fabricated using selective laser melting (SLM) combined with a powder-bed system, by applying heat treatments at temperatures of either 300 or 530°C.
Abstract: In the present study, we examined changes in the microstructure and mechanical properties of AlSi10Mg alloy, initially fabricated using selective laser melting (SLM) combined with a powder-bed system, by applying heat treatments at temperatures of either 300 or 530 °C. The as-fabricated samples exhibited a characteristic microstructural morphology and {001} texture. Melt pools corresponding to the locally melted and rapidly solidified regions were found to be composed of several columnar α-Al grains surrounded by fine eutectic Si particles. A fine dislocation substructure consisting of low-angle boundaries is present within the columnar α-Al grains. At elevated temperatures, fine Si phase precipitates within the columnar α-Al phase and coarsening of the eutectic Si particles occurs. These fine Si particles inhibit grain growth in the α-Al matrix, resulting in the microstructural morphology and [001] texture observed in the heat-treated samples. The dislocation substructure disappears in the columnar α-Al grains. Furthermore, the formation of a stable intermetallic phase occurs, reaching microstructural equilibrium after long-term exposure. The as-fabricated specimen exhibits a high tensile strength of approximately 480 MPa. The strength is independent of the tensile direction, that is, normal and parallel to the building direction. In contrast, the tensile ductility is found to be direction-dependent, and is therefore responsible for a fracture preferentially occurring at a melt pool boundary. The direction-dependence of the tensile ductility was not found in the specimen that had been heat-treated at 530 °C. The present results provide new insights into the control of the direction-dependence of the tensile properties of AlSi10Mg alloys fabricated by SLM.
344 citations
Cites background or methods or result from "Additive manufacturing of metals"
...AlSi10Mg alloy samples are described in the literature [9,10,18]....
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...New technological developments have recently been applied to the SLM process [9,10] to enable the fabrication of cellular lattice structures using a range of metals and alloys [11]....
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...These processes include the commonly used selective laser melting (SLM), selective laser sintering (SLS), direct metal laser sintering (DMLS), electron beam melting (EBM), and selective heat sintering (SHS) [9,10]....
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...4(a)) exhibits the characteristic microstructure consisting of melt pools with a half-cylindrical shape (corresponding to the locally melted and rapidly solidified regions) as reported in the literature [10,26,27]....
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TL;DR: The physics of droplet ejection under strong evaporative flow is described using simulations of the laser powder bed interactions to elucidate the experimental results and the relevance of vapor driven entrainment of metal micro-particles to similar fluid dynamic studies in other fields of science will be discussed.
Abstract: The results of detailed experiments and finite element modeling of metal micro-droplet motion associated with metal additive manufacturing (AM) processes are presented. Ultra high speed imaging of melt pool dynamics reveals that the dominant mechanism leading to micro-droplet ejection in a laser powder bed fusion AM is not from laser induced recoil pressure as is widely believed and found in laser welding processes, but rather from vapor driven entrainment of micro-particles by an ambient gas flow. The physics of droplet ejection under strong evaporative flow is described using simulations of the laser powder bed interactions to elucidate the experimental results. Hydrodynamic drag analysis is used to augment the single phase flow model and explain the entrainment phenomenon for 316 L stainless steel and Ti-6Al-4V powder layers. The relevance of vapor driven entrainment of metal micro-particles to similar fluid dynamic studies in other fields of science will be discussed.
333 citations
TL;DR: In this article, a high-performance grade 300 maraging steels were fabricated by selective laser melting (SLM) and different heat treatments were applied for improving their mechanical properties.
326 citations
TL;DR: The cold spray additive manufacturing (CSAM) has been shown to retain the original properties of the feedstock, to produce oxide-free deposits, and to not adversely influence underlying substrate materials during manufacture.
Abstract: Cold spray is a solid-state coating deposition technology which has recently been applied as an additive manufacturing process to fabricate individual components and to repair damaged components. In comparison with fusion-based high-temperature additive manufacturing processes, cold spray additive manufacturing (CSAM) has been shown to retain the original properties of the feedstock, to produce oxide-free deposits, and to not adversely influence underlying substrate materials during manufacture. Therefore, CSAM is attracting considerable attention from both scientific and industrial communities. Although CSAM is an emerging additive manufacturing technology, a body of work has been carried out by various research groups and the technology has been applied across a range of manufacturing areas. The purpose of this paper is to systematically summarize and review the CSAM-related work to date.
314 citations
TL;DR: In this paper, the authors review the literature on the influential microstructural attributes on fatigue performance of additive manufacturing (AM) parts with a focus on generated defects, including defect-based, microstructure-sensitive, and multiscale models.
309 citations
References
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TL;DR: The state-of-the-art of additive manufacturing (AM) can be classified into three categories: direct digital manufacturing, free-form fabrication, or 3D printing as discussed by the authors.
Abstract: This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.
4,055 citations
"Additive manufacturing of metals" refers background in this paper
...Schematics of an LMD set-up (from Frazier [38])....
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...Commonly repaired or produced parts are turbine blades, shafts and parts of gear mechanisms mostly made from steels, Ti and its alloys as well as Ni-based super alloys [38,39]....
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...The melt pool which is typically protected against oxidation by supplying argon or helium is produced by the energy input of an Nd:YAG, diode or CO2 laser and the metal powder is fed by a coaxial or multi-jet nozzle [38,39], cf....
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Book•
01 Dec 1994
TL;DR: The Materials Properties Handbook: Titanium Alloys as discussed by the authors provides a data base for information on titanium and its alloys, and the selection of specific alloys for specific applications, including applications, physical properties, corrosion, mechanical properties (including design allowances where available), fatigue, fracture properties, and elevated temperature properties.
Abstract: Comprehensive datasheets on more than 60 titanium alloys More than 200 pages on metallurgy and fabrication procedures Input from more than 50 contributors from several countries Careful editorial review for accuracy and usefulness Materials Properties Handbook: Titanium Alloys provides a data base for information on titanium and its alloys, and the selection of specific alloys for specific applications The most comprehensive titanium data package ever assembled provides extensive information on applications, physical properties, corrosion, mechanical properties (including design allowances where available), fatigue, fracture properties, and elevated temperature properties The appropriate specifications for each alloy are included This international effort has provided a broad information base that has been compiled and reviewed by leading experts within the titanium industry, from several countries, encompassing numerous technology areas Inputs have been obtained from the titanium industry, fabricators, users, government and academia This up-to-date package covers information from almost the inception of the titanium industry, in the 1950s, to mid-1992 The information, organized by alloy, makes this exhaustive collection an easy-to-use data base at your fingertips, which generally includes all the product forms for each alloy The 60-plus data sheets supply not only extensive graphical and tabular information on properties, but the datasheets also describe or illustrate important factors which would aid in the selection of the proper alloy or heat treatment The datasheets are further supplemented with back-ground information on the metallurgy and fabrication characteristics of titanium alloys An especially extensive coverage of properties, processing and metallurgy is provided in the datasheet for the workhorse of the titanium industry, Ti-6Al-4V This compendium includes the newest alloys made public even those still under development In many cases, key references are included for further information on a given subject Comprehensive datasheets provide extensive information on: Applications, Specifications, Corrosion, Mechanical Design Properties, Fatigue and Fracture
2,286 citations
"Additive manufacturing of metals" refers background in this paper
...It is also known that the distorted hexagonal lattice structure of the a0 martensite is stronger than lamellar a, mainly due to its fine lath width, though it does not necessarily reduce the ductility [143]....
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...Selected microstructural features and effect on properties of titanium alloys [143]....
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TL;DR: In this article, the development of the microstructure of the Ti-6Al-4V alloy processed by selective laser melting (SLM) was studied by light optical microscopy.
2,201 citations
TL;DR: The authors examines the characteristics and applications of 3D printing and compares it with mass customization and other manufacturing processes, and concludes that 3-D printing enables small quantities of customized goods to be produced at relatively low costs.
1,900 citations
Book•
01 Apr 1988
TL;DR: In this paper, the authors provide a summary of the most useful information required to understand titanium and its alloys and present a review of the significant features of the metallurgy and application of titanium and alloys.
Abstract: Designed to support the need of engineering, management, and other professionals for information on titanium by providing an overview of the major topics, this book provides a concise summary of the most useful information required to understand titanium and its alloys The author provides a review of the significant features of the metallurgy and application of titanium and its alloys All technical aspects of the use of titanium are covered, with sufficient metals property data for most users Because of its unique density, corrosion resistance, and relative strength advantages over competing materials such as aluminum, steels, and superalloys, titanium has found a niche in many industries Much of this use has occurred through military research, and subsequent applications in aircraft, of gas turbine engines, although more recent use features replacement joints, golf clubs, and bicycles Contents include: A primer on titanium and its alloys, Introduction to selection of titanium alloys, Understanding titanium's metallurgy and mill products, Forging and forming, Castings, Powder metallurgy, Heat treating, Joining technology and practice, Machining, Cleaning and finishing, Structure/processing/property relationships, Corrosion resistance, Advanced alloys and future directions, Appendices: Summary table of titanium alloys, Titanium alloy datasheets, Cross-reference to titanium alloys, Listing of selected specification and standardization organizations, Selected manufacturers, suppliers, services, Corrosion data, Machining data
1,788 citations
"Additive manufacturing of metals" refers background in this paper
...Donachie [140] b-ST aþ b colony 931 1055 9...
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