Development of high-strength WNbMoTaVZrx refractory high entropy alloys

Liu

et al. 2022

In this work, novel high-strength, low-activation Wx(TaVZr)100−x (x = 5, 10, 15, 20, 25) refractory high entropy alloys (RHEAs) were prepared by vacuum arc melting. Their microstructure, compressive mechanical properties, hardness, and fracture morphology were investigated and analyzed. The results show that the RHEAs possess a disordered BCC phase, ordered Laves phase, and Zr-rich HCP phase. Their dendrite structures were observed, and the distribution of dendrites became gradually more dense with an increase in W content. The RHEAs demonstrate high strength and hardness, with these properties being higher than in most reported tungsten-containing RHEAs. For example, the typical W20(TaVZr)80 RHEA has a yield strength of 1985 MPa and a hardness of 636 HV, respectively. The improvement in terms of strength and hardness are mainly due to solid solution strengthening and the increase in dendritic regions. During compression, with the increase in the applied load, the fracture behavior of RHEAs changed from initial intergranular fractures to a mixed mode combining both intergranular and transgranular fractures.

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Novel High-Strength, Low-Activation Wx(TaVZr)100−x (x = 5, 10, 15, 20, 25) Refractory High Entropy Alloys

Zhang

Liu

et al. 2022

“…The initially developed W-containing RHEAs generally have single-phase structures. Thereafter, studies have shown that the addition of non-refractory metal elements or non-metallic elements may cause RHEAs to form two-phase or even multiphase structures [ 45 , 74 , 75 ], improving the comprehensive properties. W has a high hardness, high melting point and relatively stable chemical properties, leading to excellent mechanical properties of W-containing RHEAs, especially for high-temperature applications.…”

Section: Microstructure Of W-containing Rheasmentioning

confidence: 99%

“…The addition of Zr in W-containing RHEAs may result in the formation of a second BCC phase [ 74 , 75 , 85 , 86 ]. Li et al [ 75 ] developed a series of WNbMoTaVZr x (x = 0.1, 0.25, 0.5, 0.75, 1.0) RHEAs and investigated the effect of Zr content on phase formation, microstructure and mechanical properties of the RHEAs. As shown in Figure 10 , with the increase in Zr content, the microstructure of the RHEA changed from a grain morphology to a dendritic structure.…”

Section: Microstructure Of W-containing Rheasmentioning

confidence: 99%

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Recent Advances in W-Containing Refractory High-Entropy Alloys—An Overview

Chen²,

Liu³

et al. 2022

During the past decade, refractory high-entropy alloys (RHEA) have attracted great attention of scientists, engineers and scholars due to their excellent mechanical and functional properties. The W-containing RHEAs are favored by researchers because of their great application potential in aerospace, marine and nuclear equipment and other high-temperature, corrosive and irradiated fields. In this review, more than 150 W-containing RHEAs are summarized and compared. The preparation techniques, microstructure and mechanical properties of the W-containing RHEAs are systematically outlined. In addition, the functional properties of W-containing RHEAs, such as oxidation, corrosion, irradiation and wear resistance have been elaborated and analyzed. Finally, the key issues faced by the development of W-containing RHEAs in terms of design and fabrication techniques, strengthening and deformation mechanisms, and potential functional applications are proposed and discussed. Future directions for the investigation and application of W-containing RHEAs are also suggested. The present work provides useful guidance for the development, processing and application of W-containing RHEAs and the RHEA components.

“…Inspired by the necessities for high-temperature applications, refractory high entropy alloys (RHEAs) have subsequently been developed in 2010, containing at least four of the nine refractory elements (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W) [ 7 , 8 , 9 ]. With outstanding mechanical properties at high temperature, RHEAs are considered as desirable candidate materials to substitute Ni-based superalloys in the future, for high-temperature applications [ 10 , 11 , 12 ]. With the application potential for aerospace, mining machinery, and nuclear fusion reactors [ 13 , 14 , 15 ], the phase formation, microstructure, and mechanical properties of RHEAs, such as strength, plastic deformation mechanisms, and fracture behavior, have been investigated extensively [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

On the WEDM of WNbMoTaZrx (x = 0.5, 1) Refractory High Entropy Alloys

Chang

et al. 2022

As a potential candidate for the next generation of high-temperature alloys, refractory high entropy alloys (RHEAs) have excellent mechanical properties and thermal stability, especially for high-temperature applications, where the processing of RHEAs plays a critical role in engineering applications. In this work, the wire electrical discharge machining (WEDM) performance of WNbMoTaZrx (x = 0.5, 1) RHEAs was investigated, as compared with tungsten, cemented carbide and industrial pure Zr. The cutting efficiency (CE) of the five materials was significantly dependent on the melting points, while the surface roughness (Ra) was not. For the RHEAs, the CE was significantly affected by the pulse-on time (ON), pulse-off time (OFF) and peak current (IP), while the surface roughness was mainly dependent on the ON and IP. The statistical analyses have shown that the CE data of RHEAs have relatively-smaller Weibull moduli than those for the Ra data, which suggests that the CE of RHEAs can be tuned by optimizing the processing parameters. However, it is challenging to tune the surface roughness of RHEAs by tailoring the processing parameters. Differing from the comparative materials, the WEDMed surfaces of the RHEAs showed dense spherical re-solidified particles at upper recast layers, resulting in larger Ra values. The proportion of the upper recast layers can be estimated by the specific discharge energy (SDE). Following the WEDM, the RHEAs maintained the main BCC1 phase, enriched with the W and Ta elements, while the second BCC2 phase in the Zr1.0 RHEA disappeared. Strategies for achieving a better WEDMed surface quality of RHEAs were also proposed and discussed.