Special Issue "Tungsten and Tungsten Alloys"

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Metal Casting, Forming and Heat Treatment".

Deadline for manuscript submissions: 30 September 2021.

Special Issue Editor

Prof. Dr. Andrey M. Litnovsky
E-Mail Website
Guest Editor
1. Senior researcher at the Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str. D-52425 Jülich, Germany
2. Teaching Professor at the National Research Nuclear University MEPhI, Moscow, Russian Federation, Kashirskoe sh., 31, 115409 Moscow, Russia
Interests: refractory metals; self-passivating alloys; single crystals; metallic mirrors; plasma-facing materials; materials for extreme environments; mechanical alloying; field-assisted sintering technology; materials modeling; materials engineering; surface diagnostics; plasma–surface interactions and plasma diagnostics

Special Issue Information

Dear Colleagues,

Tungsten, one of the most remarkable refractory materials, has attracted the attention of scientists and engineers for the last two centuries. The technological boom we are currently witnessing has significantly advanced our knowledge and understanding of this extraordinary metal. The application range of tungsten has significantly expanded, and now we can see this material applied in automotive and lighting industries, shipbuilding, aerospace, medicine, heavy machinery, mining, and many other areas of our lives.

Besides the ultimate advantages of tungsten (e.g., the highest melting point among all metals, high thermal conductivity at elevated temperatures, heavy mass, relatively low induced activation), there are some properties which until now had limited the potential application of this metal. These properties, such as the intrinsic brittleness of tungsten and its vulnerability to oxidation, were formerly accepted as given by nature. Presently, however, inspired by the unprecedented technological development, modern machinery, highly sophisticated modeling, advanced engineering, and fantastic analytic tools, scientists and engineers “dare” to change these properties as well.

One of the most prominent examples of these developments comes from the area of the controlled fusion, the energy source of the stars—one of the most challenging environments imaginable so far. Here, tungsten has found its place as the material protecting the interior of the power station from the hot fusion plasma. New advanced technology, nano-engineering, and sophisticated alloying have helped to turn the disadvantageous properties of tungsten back and to attain the qualities of this material which it had never possessed before. In this Special Issue devoted to tungsten and tungsten alloys, we will see the results of these challenging, but remarkable and fascinating, transformations of tungsten.

I would like to take this opportunity to welcome you to this Special Issue of Metals devoted to tungsten and tungsten alloys. Please enjoy reading the selected articles devoted to the recent developments in the science, technology, and engineering of tungsten. I am also kindly inviting you to share your own research by contributing with your own manuscript to this Special Issue.

I am looking forward to hearing from you.

Prof. Dr. Andrey M. Litnovsky
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Tungsten
  • Tungsten alloys
  • High-entropy alloys
  • Smart materials
  • Corrosion
  • Materials modeling
  • Fusion
  • Plasma–material interaction
  • Field-assisted sintering technology
  • Hot isostatic pressing
  • Mechanical alloying

Published Papers (4 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

Article
Brazing Tungsten/Tantalum/RAFM Steel Joint for DEMO by Fully Reduced Activation Brazing Alloy 48Ti-48Zr-4Be
Metals 2021, 11(9), 1417; https://doi.org/10.3390/met11091417 - 07 Sep 2021
Viewed by 302
Abstract
To create a DEMO reactor, it is necessary to develop high-quality technology to join tungsten with reduced-activation ferritic-martensitic (RAFM) steel (Rusfer, Eurofer, CLF-1, etc.). Difficulties arise in their direct connection due to the large difference in the coefficient of thermal expansion (CTE). To [...] Read more.
To create a DEMO reactor, it is necessary to develop high-quality technology to join tungsten with reduced-activation ferritic-martensitic (RAFM) steel (Rusfer, Eurofer, CLF-1, etc.). Difficulties arise in their direct connection due to the large difference in the coefficient of thermal expansion (CTE). To suppress the difference of CTE, intermediate interlayers are usually used, such as vanadium or tantalum, and brazing is a prospective technology to conduct the joining. The vast majority of works represent copper- or nickel-based brazing alloys, but their applicability is under significant discussion due to their activation properties. That is why, in this work, fully reduced activation 48Ti-48Zr-4Be wt.% brazing alloy was used. The following joint was made: Rusfer steel/48Ti-48Zr-4Be/Ta/48Ti-48Zr-4Be/W. The brazing was successfully carried out under a mode providing thermal heat treatment of Rusfer. Through EDS and EBSD analysis, the microstructure of the joint was determined. Shear strength of the as-joined composition was measured as 127 ± 20 MPa. The joint endured 200 thermocycles in the temperature range between 300–600 °C, but the fillet regions degraded. Full article
(This article belongs to the Special Issue Tungsten and Tungsten Alloys)
Show Figures

Figure 1

Article
Improving the W Coating Uniformity by a COMSOL Model-Based CVD Parameter Study for Denser Wf/W Composites
Metals 2021, 11(7), 1089; https://doi.org/10.3390/met11071089 - 08 Jul 2021
Cited by 1 | Viewed by 499
Abstract
Tungsten (W) has the unique combination of excellent thermal properties, low sputter yield, low hydrogen retention, and acceptable activation. Therefore, W is presently the main candidate for the first wall and armor material for future fusion devices. However, its intrinsic brittleness and its [...] Read more.
Tungsten (W) has the unique combination of excellent thermal properties, low sputter yield, low hydrogen retention, and acceptable activation. Therefore, W is presently the main candidate for the first wall and armor material for future fusion devices. However, its intrinsic brittleness and its embrittlement during operation bears the risk of a sudden and catastrophic component failure. As a countermeasure, tungsten fiber-reinforced tungsten (Wf/W) composites exhibiting extrinsic toughening are being developed. A possible Wf/W production route is chemical vapor deposition (CVD) by reducing WF6 with H2 on heated W fabrics. The challenge here is that the growing CVD-W can seal gaseous domains leading to strength reducing pores. In previous work, CVD models for Wf/W synthesis were developed with COMSOL Multiphysics and validated experimentally. In the present article, these models were applied to conduct a parameter study to optimize the coating uniformity, the relative density, the WF6 demand, and the process time. A low temperature and a low total pressure increase the process time, but in return lead to very uniform W layers at the micro and macro scales and thus to an optimized relative density of the Wf/W composite. High H2 and low WF6 gas flow rates lead to a slightly shorter process time and an improved coating uniformity as long as WF6 is not depleted, which can be avoided by applying the presented reactor model. Full article
(This article belongs to the Special Issue Tungsten and Tungsten Alloys)
Show Figures

Figure 1

Article
Characteristics of Microstructure Evolution during FAST Joining of the Tungsten Foil Laminate
Metals 2021, 11(6), 886; https://doi.org/10.3390/met11060886 - 28 May 2021
Viewed by 680
Abstract
The tungsten (W) foil laminate is an advanced material concept developed as a solution for the low temperature brittleness of W. However, the deformed W foils inevitably undergo microstructure deterioration (crystallization) during the joining process at a high temperature. In this work, joining [...] Read more.
The tungsten (W) foil laminate is an advanced material concept developed as a solution for the low temperature brittleness of W. However, the deformed W foils inevitably undergo microstructure deterioration (crystallization) during the joining process at a high temperature. In this work, joining of the W foil laminate was carried out in a field-assisted sintering technology (FAST) apparatus. The joining temperature was optimized by varying the temperature from 600 to 1400 °C. The critical current for mitigating the microstructure deterioration of the deformed W foil was evaluated by changing the sample size. It is found that the optimal joining temperature is 1200 °C and the critical current density is below 418 A/cm2. According to an optimized FAST joining process, the W foil laminate with a low microstructure deterioration and good interfacial bonding can be obtained. After analyzing these current profiles, it was evident that the high current density (sharp peak current) is the reason for the significant microstructure deterioration. An effective approach of using an artificial operation mode was proposed to avoid the sharp peak current. This study provides the fundamental knowledge of FAST principal parameters for producing advanced materials. Full article
(This article belongs to the Special Issue Tungsten and Tungsten Alloys)
Show Figures

Figure 1

Review

Jump to: Research

Review
Advanced Self-Passivating Alloys for an Application under Extreme Conditions
Metals 2021, 11(8), 1255; https://doi.org/10.3390/met11081255 - 09 Aug 2021
Viewed by 398
Abstract
Self-passivating Metal Alloys with Reduced Thermo-oxidation (SMART) are under development for the primary application as plasma-facing materials for the first wall in a fusion DEMOnstration power plant (DEMO). SMART materials must combine suppressed oxidation in case of an accident and an acceptable plasma [...] Read more.
Self-passivating Metal Alloys with Reduced Thermo-oxidation (SMART) are under development for the primary application as plasma-facing materials for the first wall in a fusion DEMOnstration power plant (DEMO). SMART materials must combine suppressed oxidation in case of an accident and an acceptable plasma performance during the regular operation of the future power plant. Modern SMART materials contain chromium as a passivating element, yttrium as an active element and a tungsten base matrix. An overview of the research and development program on SMART materials is presented and all major areas of the structured R&D are explained. Attaining desired performance under accident and regular plasma conditions are vital elements of an R&D program addressing the viability of the entire concept. An impressive more than 104-fold suppression of oxidation, accompanied with more than 40-fold suppression of sublimation of tungsten oxide, was attained during an experimentally reproduced accident event with a duration of 10 days. The sputtering resistance under DEMO-relevant plasma conditions of SMART materials and pure tungsten was identical for conditions corresponding to nearly 20 days of continuous DEMO operation. Fundamental understanding of physics processes undergone in the SMART material is gained via fundamental studies comprising dedicated modeling and experiments. The important role of yttrium, stabilizing the SMART alloy microstructure and improving self-passivating behavior, is under investigation. Activities toward industrial up-scale have begun, comprising the first mechanical alloying with an industrial partner and the sintering of a bulk SMART alloy sample with dimensions of 100 mm × 100 mm × 7 mm using an industrial facility. These achievements open the way to further expansion of the SMART technology toward its application in fusion and potentially in other renewable energy sources such as concentrated solar power stations. Full article
(This article belongs to the Special Issue Tungsten and Tungsten Alloys)
Show Figures

Figure 1

Back to TopTop