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Book ChapterDOI

Production of titanium by the Armstrong Process

01 Jan 2015-pp 149-162
TL;DR: The Armstrong Process as discussed by the authors is a powder production process capable of producing commercially pure titanium and Ti-6Al-4V by the reduction of titanium tetrachloride and other metal halides by sodium.
Abstract: The Armstrong Process® is a novel powder production process capable of producing commercially pure titanium and Ti-6Al-4V by the reduction of titanium tetrachloride and other metal halides by sodium The process produces powder particles with a unique, low bulk density, “coral-like” morphology Postprocessing activities such as dry and wet ball milling provide a means of increasing the tap density and narrowing the particle size distribution to meet the requirements for typical powder metallurgy conversion processes The Armstrong Process powder’s unique morphology produces excellent compressibility and compaction behavior, capable of producing compacts with significantly higher green strength than other irregular powders Powders can be consolidated by traditional powder metallurgy techniques such as uniaxial compaction and cold isostatic pressing Optimal parameters for consolidation via such techniques have been established The high degree of interlocking between adjacent powder particles offers distinct advantages in roll compaction, allowing for the direct rolling of powder into titanium sheet Examinations of the sintering behavior of compacts produced from The Armstrong Process powders show that the higher surface area-to-volume ratio of the material results in the onset of sintering and shrinkage at a much lower temperature than other powders As result, less aggressive sintering conditions are required for near-full densification The Armstrong Process powders can be spheroidized by plasma induction as a means of increasing overall tap density and powder flow rate to make it ideal for applications such as metal injection molding and additive manufacturing
Citations
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Journal ArticleDOI
TL;DR: A review of the most widely used additive manufacturing (AM) techniques for biomedical applications is presented in this paper, where special attention has been paid on Fused deposition modeling (FDM) based AM technique as it is economical, environmentally friendly and adaptable to flexible filament material.

575 citations

Journal ArticleDOI
TL;DR: Powder metallurgy (PM) of titanium is a potentially cost-effective alternative to conventional wrought titanium as mentioned in this paper, which examines both traditional and emerging technologies, including the prod...,.
Abstract: Powder metallurgy (PM) of titanium is a potentially cost-effective alternative to conventional wrought titanium. This article examines both traditional and emerging technologies, including the prod...

336 citations


Cites background from "Production of titanium by the Armst..."

  • ...nearly perfect round shape as the other atomised powders [6,122]....

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Journal ArticleDOI
15 Aug 2017-JOM
TL;DR: In this article, the authors provide a cursory review of the basic techniques of commercial and emerging methods for making spherical titanium alloy powder and the advantages as well as limitations of different methods are discussed.
Abstract: Spherical titanium alloy powder is an important raw material for near-net-shape fabrication via a powder metallurgy (PM) manufacturing route, as well as feedstock for powder injection molding, and additive manufacturing (AM). Nevertheless, the cost of Ti powder including spherical Ti alloy has been a major hurdle that prevented PM Ti from being adopted for a wide range of applications. Especially with the increasing importance of powder-bed based AM technologies, the demand for spherical Ti powder has brought renewed attention on properties and cost, as well as on powder-producing processes. The performance of Ti components manufactured from powder has a strong dependence on the quality of powder, and it is therefore crucial to understand the properties and production methods of powder. This article aims to provide a cursory review of the basic techniques of commercial and emerging methods for making spherical Ti powder. The advantages as well as limitations of different methods are discussed.

149 citations

Journal ArticleDOI
TL;DR: In this paper, a novel method was developed to produce spherical Ti-6Al-4V powder for advanced near-net-shape manufacturing processes including additive manufacturing and powder injection molding.

92 citations

Journal ArticleDOI
TL;DR: In this paper, a method to manufacture low-porosity titanium components at high deposition efficiencies is revealed by combining low-pressure cold spray using nitrogen as the carrier gas with low-cost titanium powder produced using the Armstrong process.
Abstract: Titanium parts are ideally suited for aerospace applications due to their unique combination of high specific strength and excellent corrosion resistance. However, titanium as bulk material is expensive and challenging/costly to machine. Production of complex titanium parts through additive manufacturing looks promising, but there are still many barriers to overcome before reaching mainstream commercialization. The cold gas dynamic spraying process offers the potential for additive manufacturing of large titanium parts due to its reduced reactive environment, its simplicity to operate, and the high deposition rates it offers. A few challenges are to be addressed before the additive manufacturing potential of titanium by cold gas dynamic spraying can be reached. In particular, it is known that titanium is easy to deposit by cold gas dynamic spraying, but the deposits produced are usually porous when nitrogen is used as the carrier gas. In this work, a method to manufacture low-porosity titanium components at high deposition efficiencies is revealed. The components are produced by combining low-pressure cold spray using nitrogen as the carrier gas with low-cost titanium powder produced using the Armstrong process. The microstructure and mechanical properties of additive manufactured titanium components are investigated.

73 citations

References
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Journal Article
TL;DR: The conventional cold compaction-and-sinter powder metallurgy (PM) approach offers an efficient solution to the near-net shape or preform fabrication of titanium and its alloys for cost reduction and improved chemical homogeneity and refined microstructures as discussed by the authors.
Abstract: The conventional cold-compaction-and-sinter powder metallurgy (PM) approach offers an efficient solution to the near-net shape or preform fabrication of titanium and its alloys for cost reduction and improved chemical homogeneity and refined microstructures. The methods for compacting titanium powder are similar to those used for other ductile powders. The high-purity titanium in the most ductile state is similar to annealed copper in terms of elastic modulus, hardness, elongation, and ultimate tensile strength. The properties of titanium are sensitive to the impurity level, in particular to nitrogen, oxygen, carbon, and iron. Hardness is a convenient measure of the quality of a titanium sponge product. Dilatometric studies of the sintering of titanium-nickel alloys show similar observations and confirm that oxide films on titanium powder surfaces do not need to be reduced by the atmosphere or disrupted by a chemical additive.

143 citations