Room‐Temperature Mechanical Properties of V₂₀Nb₂₀Mo₂₀Ta₂₀W₂₀ High‐Entropy Alloy

Abstract

Refractory high‐entropy alloys (HEAs) have shown promising high temperature strengths, while their mechanical behaviors at room temperature are rarely reported. In this work, the room‐temperature mechanical properties of V20Nb20Mo20Ta20W20 refractory HEA under various different loading modes including tension, compression, bending, shear loading, and microhardness are investigated. The results show that this alloy exhibits very high compressive strength but quite low strengths under tension, bending, and shear loading, similar to the conventional brittle materials. However, pronounced plasticity and slip bands are observed in compression samples, and no indentation cracking is observed in low‐load microhardness tests, which indicate the potential ability of plastic deformation in this refractory HEA. The present work suggests that the microstructure or composition of this HEA should be carefully tailored before its practical usage to suppress its large tendency for cracking and eventually improve its ductility and strength under tension.

Powder Metallurgy Route to Ultrafine‐Grained Refractory Metals

“…However, it is in doubt whether the stabilized structure is induced by its high configurational entropy or the GB pining effect of in situ formed second phase particles. It is believed that oxyphilic composition elements such as Ta preferentially react with oxygen to form Ta oxide particles before [65,[223][224][225][226][227][228][229][230][231][232][233][234] MA combined with SPS, [67,69,227,[235][236][237][238][239][240][241][242][243][244] magnesiothermal synthesis combined with SPS, and nitridation synthesis combined with SPS route. The second-phase dispersed structure and the metal (BCC)-ceramic (FCC) interconnected structure are recently produced by our group.…”

“…Figure 14. Schematic diagram of the representative microstructure of RHEAs synthesized by arc melting,[65,[223][224][225][226][227][228][229][230][231][232][233][234] MA combined with SPS,[67,69,227,[235][236][237][238][239][240][241][242][243][244] magnesiothermal synthesis combined with SPS, and nitridation synthesis combined with SPS route. The second-phase dispersed structure and the metal (BCC)-ceramic (FCC) interconnected structure are recently produced by our group.…”

Development and Property Tuning of Refractory High-Entropy Alloys: A Review

“…In addition, the lattice distortion and the interaction between atoms also have a significant mitigation effect on the co-diffusion of atoms in RHEAs. Therefore, at high temperatures, RHEAs are not prone to produce phase transformation, and these can also have higher high-temperature strength [79,80]. From the mechanical point of view, these characteristics are the key mechanism to determine whether high-temperature alloy materials can be applied in a hightemperature field.…”

A Review of the Latest Developments in the Field of Refractory High-Entropy Alloys

“…Different materials have been developed to increase the ability to withstand challenging environments, efficiency, and safety of materials. Refractory high-entropy alloys were developed in 2010 [1] with the primary purpose of withstanding high temperatures and to act as replacements for Ni-based superalloys and other applications, such as anodes for X-ray production gas turbine blades, armor, aerospace, and structural applications [2]. From the thermodynamic perspective, configurational entropy increases with an increasing number of elements, leading to high-entropy alloys (HEAs) [3].…”