Structural evolution in TiZrHfNb high-entropy alloy

Ryltsev, R. E.; Эстемирова, С. Х.; Гавико, В. С.; Yagodin, D. A.; Bykov, Viktor; Sterkhov, Evgenii; Cherepanova, L. A.; Sipatov, I. S.; Balyakin, I. A.; Упоров, С. А.

doi:10.1016/j.mtla.2021.101311

Cited by 21 publications

(3 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The thermal stability of MPEAs depends on both the chemical composition and the microstructure. For example, an as-cast single phase HfNbTiZr MPEA was stable at 673 K for 100 h, while precipitates appeared after 200 h at the same temperature, and after 700 h the material consisted of two bcc phases and an additional hcp phase [20]. Cao et al [21] performed annealing for 100 h at different temperatures on the same MPEA, confirming that at 673 K elemental segregation occurs, but there was no formation of extra crystalline phases.…”

Section: Introductionmentioning

confidence: 94%

Influence of Degree of Severe Plastic Deformation on Thermal Stability of an HfNbTiZr Multi-Principal Element Alloy Processed by High-Pressure Torsion

et al. 2022

View full text Add to dashboard Cite

Severe plastic deformation (SPD) is an effective route for the nanocrystallization of multi-principal element alloys (MPEAs). The stability of the refined microstructure is important, considering the high temperature applications of these materials. In the present study, the effect of SPD on the stability of a body-centered cubic (bcc) HfNbTiZr MPEA was investigated. SPD was performed using a high-pressure torsion (HPT) technique by varying the number of turns between ½ and 10. The evolution of phase composition and microstructure was studied near the disk centers and edges where the imposed strain values were the lowest and highest, respectively. Thus, the shear strain caused by HPT varies between 3 (½ turn, near the center) and 340 (10 turns, near the edge). It was found that during annealing up to 1000 K, the bcc HfNbTiZr alloy decomposed into two bcc phases with different lattice constants at 740 K. In addition, at high strains a hexagonal close packed (hcp) phase was formed above 890 K. An inhomogeneous elemental distribution was developed at temperatures higher than 890 K due to the phase decomposition. The scale of the chemical heterogeneities decreased from about 10 µm to 30 nm where the shear strain increased from 3 to 340, which is similar to the magnitude of grain refinement. Anneal-induced hardening was observed in the MPEA after HPT for both low and high strains at 740 K, i.e., the hardness of the HPT-processed samples increased due to heat treatment. At low strain, the hardness remained practically unchanged between 740 and 1000 K, while for the alloy receiving high strains there was a softening in this temperature range.

show abstract

Section: Introductionmentioning

confidence: 94%

Influence of Degree of Severe Plastic Deformation on Thermal Stability of an HfNbTiZr Multi-Principal Element Alloy Processed by High-Pressure Torsion

et al. 2022

View full text Add to dashboard Cite

show abstract

“…In the case of a random atom distribution, α ij are equal to zero. As follows from our practice of studying Warren-Cowley parameters for multielement alloys [30,31], the values |α| < 0.05 can be treated as zeros within the calculation accuracy. As seen in Fig.…”

Section: Ab Initio Simulationmentioning

confidence: 99%

Magnetocaloric Effect in ScGdHo Medium-entropy Alloy

Упоров

Sterkhov

Balyakin

2022

Preprint

View full text Add to dashboard Cite

The search for eﬀective solid-state refrigerant for magnetocaloric application is one of the main-stream topics in materials science. Rareearth multi-principal element alloys seem to be promising candidates for these purposes. In this study, we address the issues of structure formation, magnetic and magnetocaloric properties in ScGdHo medium entropy alloy. We perform the ab initio molecular dynamics simulations for the liquid and solid phases in this system and reveal a strong tendency to form a single-phase solid solu-tion. The experimentally fabricated alloy demonstrates a single-phase HCP crystalline structure with high density of defects. The magnetic measurements reveal a complicated magnetic behaviour in the material. The alloy exhibits antiferromagnetic or ferromagnetic behavior depending on the magnetic ﬁeld. We have found that AFM order is preferable under a weak magnetic ﬁeld and FM order occurs when the ﬁeld strength exceeds 12 kOe. The alloy reveals a rather large coercive force in a wide temperature range up to the Neel point. The values of the magnetic entropy change and relative cooling power calculated for a magnetic ﬁeld change of 0-5 T are 8.93 Jkg−1K−1 and 938 J/kg, respectively. The examined ScGdHo alloy demonstrates the best magnetocaloric properties among similar rareearth metal materials discovered to date.

show abstract

“…Indeed, by cooling a metallic melt, one can obtain a phase which is not thermodynamically stable but can exist at given conditions for very long times. For example, multicomponent high-entropy alloys can form single-phase solid solutions in as-cast state, which can be treated as practically stable and decompose only after very long (up to months) annealing (see [51]).…”

Section: Pair Correlation Functions and Effective Parametersmentioning

confidence: 99%

Freezing in two-length-scale systems: complexity, universality and prediction

Ryltsev¹,

Chtchelkatchev²

2022

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Two-length-scale pair potentials arise ubiquitously in condensed matter theory as effective interparticle interactions in molecular, metallic and soft matter systems. The existence of two different bond lengths generated by the shape of potential causes complicated behavior in even one-component systems: polymorphism in solid and liquid states, water-like anomalies, the formation of quasicrystals and high stability against crystallization. Here we address general properties of freezing in one-component two-length-scale systems and argue that solidification of a liquid during cooling is essentially determined by the radial distribution function (RDF) of the liquid. We show that different two-length-scale systems having similar RDFs freeze into the same solid phases. In some cases, the similarity between RDFs can be expressed by the proximity of two dimensionless effective parameters: the ratio between effective bond lengths, $\lambda$, and the fraction of short-bonded particles $\phi$. We validate this idea by studying the formation of different solid phases in different two-length-scale systems. The method proposed allows predicting effectively the formation of solid phases in both numerical simulations and self-assembling experiments in soft matter systems with tunable interactions.

show abstract

Structural evolution in TiZrHfNb high-entropy alloy

Cited by 21 publications

References 43 publications

Influence of Degree of Severe Plastic Deformation on Thermal Stability of an HfNbTiZr Multi-Principal Element Alloy Processed by High-Pressure Torsion

Influence of Degree of Severe Plastic Deformation on Thermal Stability of an HfNbTiZr Multi-Principal Element Alloy Processed by High-Pressure Torsion

Magnetocaloric Effect in ScGdHo Medium-entropy Alloy

Freezing in two-length-scale systems: complexity, universality and prediction

Contact Info

Product

Resources

About