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Coatings based on refractory metals and compounds have been used in various industries since the last century due to their high thermal and heat resistance, as well as their excellent mechanical and tribological properties. Advances have made it possible to apply high-tech methods for their production, which has improved their availability and expanded their range of applications. A promising area of use of coatings based on refractory systems is the anticorrosion protection of structural materials. The high wear resistance and anticorrosion ability of these materials will allow for the protection of critical units of equipment of various industries from the complex destructive effects of factors of chemical and mechanical nature. For the effective choice of coating composition, it is necessary to know the basic characteristics of refractory material layers and the method of their production. The purpose of this article is to summarize modern scientific data on methods of obtaining refractory coatings, as well as on their composition, structure, and protective properties. The information presented in this review will bridge the gap between research and industrial development and expand the niche area of utilization.

Tungsten heavy alloys are two-phase metal matrix composites that include W–Ni–Fe and W–Ni–Cu. The significant feature of these alloys is their ability to acquire both strength and ductility. In order to improve the mechanical properties of the basic alloy and to limit or avoid the need for post-processing techniques, other elements are doped with the alloy and performance studies are carried out. This work focuses on the developments through the years in improving the performance of the classical tungsten heavy alloy of W–Ni–Fe through doping of other elements. The influence of the percentage addition of rare earth elements of yttrium, lanthanum, and their oxides and refractory metals such as rhenium, tantalum, and molybdenum on the mechanical properties of the heavy alloy is critically analyzed. Based on the microstructural and property evaluation, the effects of adding the elements at various proportions are discussed. The addition of molybdenum and rhenium to the heavy alloy gives good strength and ductility. The oxides of yttrium, when added in a small quantity, help to reduce the tungsten’s grain size and obtain good tensile and compressive strengths at high temperatures.

Selective laser melting (SLM) additive manufacturing of pure tungsten encounters nearly all intractable difficulties of SLM metals fields due to its intrinsic properties. The key factors, including powder characteristics, layer thickness, and laser parameters of SLM high density tungsten are elucidated and discussed in detail. The main parameters were designed from theoretical calculations prior to the SLM process and experimentally optimized. Pure tungsten products with a density of 19.01 g/cm 3 (98.50% theoretical density) were produced using SLM with the optimized processing parameters. A high density microstructure is formed without significant balling or macrocracks. The formation mechanisms for pores and the densification behaviors are systematically elucidated. Electron backscattered diffraction analysis confirms that the columnar grains stretch across several layers and parallel to the maximum temperature gradient, which can ensure good bonding between the layers. The mechanical properties of the SLM-produced tungsten are comparable to that produced by the conventional fabrication methods, with hardness values exceeding 460 HV 0.05 and an ultimate compressive strength of about 1 GPa. This finding offers new potential applications of refractory metals in additive manufacturing.

Highly successful advanced manufacturing techniques of refractory metals are becoming increasingly necessary to navigate technology gaps. Refractory metal alloys are desirable to meet the need for high temperature structural materials, but are difficult to produce because of their high strength, low ductility, and high melting point. This work demonstrates the use of laser powder bed fusion to produce several Mo-Re alloys by additively manufacturing mechanically mixed pure elemental powders. Relationships are explored between mechanical properties regarding build orientation, laser speed, rhenium alloy content, and the addition of 3% hydrogen to the argon shield gas. Mechanical characterization was accomplished by three-point flexural testing. Rhenium content, hydrogen addition to the shield gas, and build orientation were all found to significantly affect the flexural strength. The build direction had the highest influence, and a maximum strength of 833.3 MPa was achieved in the vertical direction while the maximum strength in the horizontal direction was 346.1 MPa.

There is a growing focus on sustainability, characterized by making changes that anticipate future needs and adapting them to present requirements. Sustainability is reflected in various areas of materials science as well. Thus, more research is focused on the fabrication of advanced materials based on earth-abundant metals. The role of iron and its alloys is particularly significant as iron is the second most abundant metal on our planet. Additionally, the electrochemical method offers an environmentally friendly approach for synthesizing multifunctional alloys. Thus, iron can be successfully codeposited with a targeted metal from complexing electrolytes, opening a large horizon for a smart tuning of properties and enabling various applications. In this review, we discuss the practical aspects of the electrodeposition of iron-based alloys from complexing electrolytes, with a focus on refractory metals as multifunctional materials having magnetic, catalytic, mechanical, and antimicrobial/antibacterial properties with advanced thermal, wear, and corrosion resistance. Peculiarities of electrodeposition from complexing electrolytes are practically significant as they can greatly influence the final structure, composition, and designed properties by adjusting the electroactive complexes in the solution. Moreover, these alloys can be further upgraded into composites, multi-layered, hybrid/recovered materials, or high-entropy alloys.

Refractory metal single crystals have been applied in key high-temperature structural components of advanced nuclear reactor power systems, due to their excellent high-temperature properties and outstanding compatibility with nuclear fuels. Although electron beam floating zone melting and plasma arc melting techniques can prepare large-size oriented refractory metals and their alloy single crystals, both have difficulty producing perfect defect-free single crystals because of the high-temperature gradient. The mechanical properties of refractory metal single crystals under different loads all exhibit strong temperature and crystal orientation dependence. Slip and twinning are the two basic deformation mechanisms of refractory metal single crystals, in which low temperatures or high strain rates are more likely to induce twinning. Recrystallization is always induced by the combined action of deformation and annealing, exhibiting a strong crystal orientation dependence. The irradiation hardening and neutron embrittlement appear after exposure to irradiation damage and degrade the material properties, attributed to vacancies, dislocation loops, precipitates, and other irradiation defects, hindering dislocation motion. This paper reviews the research progress of refractory metal single crystals from three aspects, preparation technology, deformation behavior, and irradiation damage, and highlights key directions for future research. Finally, future research directions are prospected to provide a reference for the design and development of refractory metal single crystals for nuclear applications.

The most promising directions of the development of heat-resistant alloys (HRAs) based on refractory metals are analyzed. The microstructures characteristic of HRAs, which it is advisable to form in promising alloys, are considered. The stability factors of the microstructure with respect to the diffusion coarsening of the hardening phases are discussed. Two groups of alloys are considered as the most promising HRAs based on refractory metals. First, the principles for design of HRAs based on (Pt, Ir)-Sc with heterophase γ-γ’ microstructure, where γ-matrix is a (Pt, Ir) solid solution with a FCC lattice, and γ’ is a strengthening phase with the structure L12 by analogy with Ni-base superalloys, are developed. The resistance of γ-γ’ microstructure in Ni, Pt and Ir alloys against the process of diffusion-limited coarsening is analyzed. It is shown that the diffusion permeability of Pt is several times less than that of Ni, so one should expect that Pt-based HRAs will not be inferior to Ni-based HRAs in terms of structural stability. The second group includes HRAs based on many not noble refractory metals. It is shown that solid solutions of the system (Ti, Zr, Hf, Ta, Nb) with a BCC lattice can be considered as a matrix of advanced refractory HRAs. The results of experimental studies of alloys based on (Ti, Zr, Hf, Ta, Nb) additionally alloyed with elements contributing to the formation of strengthening intermetallic and silicide phases are discussed. The issues of segregation of alloying elements at the grain boundaries of refractory alloys and the effect of segregation on the cohesive strength of the boundaries are considered.

In this paper, a theoretical simulation based on a finite-difference time-domain method (FDTD) shows that the solar absorber can reach ultra-broadband and high-efficiency by refractory metals titanium (Ti) and titanium nitride (TiN). In the absorption spectrum of double-size cross-shaped absorber, the absorption bandwidth of more than 90% is 1182 nm (415.648–1597.39 nm). Through the analysis of the field distribution, we know the physical mechanism is the combined action of propagating plasmon resonance and local surface plasmon resonance. After that, the paper has a discussion about the influence of different structure parameters, polarization angle and angle of incident light on the absorptivity of the absorber. At last, the absorption spectrum of the absorber under the standard spectrum of solar radiance Air Mass 1.5 (AM1.5) is studied. The absorber we proposed can be used in solar energy absorber, thermal photovoltaics, hot-electron devices and so on.

Metal matrix composites with a matrix of refractory metals (niobium, tungsten) and reinforcing nanodiamond particles were prepared for studying the possibility of decreasing the starting temperature of carbide synthesis. The size of primary nanodiamond particles was 4–6 nm, but they were combined in large-sized agglomerates. Mechanical alloying was used for producing the composites by crushing agglomerates and distributing nanodiamonds evenly in the metal matrix. The initial and fabricated materials were investigated by X-ray diffraction, differential scanning calorimetry, and transmission and scanning electron microscopy. Thermal processing leads to the reaction for carbide synthesis. Studies have found that the usage of carbon nanoparticles (nanodiamonds) as precursors for fabricating carbides of refractory metals leads to a dramatic decrease in the synthesis temperature in comparison with macro-precursors: lower than 200 °C for tungsten and lower than 350 °C for niobium.

Recently, the wide bandgap semiconductors, especially silicon carbide (SiC), have become more important due to the unique electrical and thermophysical properties that make them applicable to a variety of electronic devices (Schottky and PiN diodes, JFETs, MOSFETs, etc.). For these applications, the crystals need to be manufactured with highest possible quality, both structural and chemical, at reduced cost. This requirement places rather extreme constraints on the crystal growth as the simultaneous goals of high quality and low cost are generally incompatible.Refractory metal carbide technology, particularly, tantalum carbide (TaC), was originally developed for application in highly corrosive and reactive environments. Yu. Vodakov [1] demonstrated for the first time advantages of use of refractory metal carbides for PVT growth of SiC and later AlN bulk crystals. In the present paper we discuss the effect of refractory metal on PVT growth of large diameter 4H SiC bulk crystals.