Metastable high entropy alloys of TiZrHfTa with glass-like characteristics at low temperatures

Zhang, Yanhui; Zhou, Yunkai; Wang, Limin; Sanvito, Stefano

doi:10.1016/j.actamat.2023.119031

Cited by 7 publications

(5 citation statements)

References 38 publications

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“…In a previous work we have learned that there is a close correlation between the width of the cDOS and the evolution of the metastability (79). Panels (a) and (b) of Fig.…”

Section: Characteristic Temperatures To Classify Multi-component Alloysmentioning

confidence: 66%

“…A DFT training dataset for the CE surrogate model is constructed by including a large variety of structures from the Ti-Zr-Hf-Nb-Ta system across a wide composition range, including elementary, binary, ternary, quaternary and quinary alloys. A total of 2,482 prototypes are built from the enumeration structure-searching technique (78), whose efficiency in mapping a wide spectrum of structure and energy distributions has been validated in our previous work (79).…”

Section: Energetic Models Of Cluster Expansionmentioning

confidence: 99%

“…Details on how to optimize the CE energetic model can be found in our previous works (32,79). Here, the integrated cluster expansion toolkit (ICET) (31) is applied for optimizing the CE Hamiltonian of the bcc Ti-Zr-Hf-Nb-Ta alloy system based on machine learning techniques.…”

Section: Energetic Models Of Cluster Expansionmentioning

confidence: 99%

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Towards quantifying (meta-)stability of multi-principal element alloys: from configurational entropy to characteristic temperatures

Zhang,

Zhou,

Dong

et al. 2023

Preprint

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Understanding the thermodynamics of multi-principal-element alloys (MPEAs), although crucial for their design, remains an elusive task. The configurational entropy, Sconf, is a critical thermodynamic quantity determining stability, but its calculation for real materials poses a hard computational challenge. Strong of a highly efficient cluster expansion, constructed on density functional theory data,and of an advanced sampling technique, we are able to compute Sconf over the huge configurational and compositional space of the prototype bcc Ti-Zr-Hf-Nb-Ta system. In particular, we explore around 200,000 atomic arrangements across more than 200 compositions. The main features of the computed Sconf-vs-temperature curves can be captured by the definition of two characteristic temperatures, which are then used to define a dimensionless descriptor. This, together with Sconf, enable us to rank alloys according to their (meta- )stability across a broad composition range, going from equiatomic to nonequiatomic, and even to the regions covered by conventional alloys. Such classification is informed and validated against hundreds of experimental results. Our analysis allows us to revise the classification scheme of alloys into high-entropy, medium-entropy and low-entropy and, in general, sheds light into the thermodynamic origin of their metastability, ultimately helping in the design and development.

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“…In a previous work we have learned that there is a close correlation between the width of the cDOS and the evolution of the metastability (79). Panels (a) and (b) of Fig.…”

Section: Characteristic Temperatures To Classify Multi-component Alloysmentioning

confidence: 66%

Section: Energetic Models Of Cluster Expansionmentioning

confidence: 99%

See 1 more Smart Citation

Towards quantifying (meta-)stability of multi-principal element alloys: from configurational entropy to characteristic temperatures

Zhang,

Zhou,

Dong

et al. 2023

Preprint

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“…where E sys AlCuFeMn is the total free energy at 0 K, F el (V, T) is the electronic free energy, F vib (V, T) is the vibrational free energy, and S conf , S lat , and S mag are entropies concerning the configurational, lattice mismatch, and magnetism of a system, respectively. The magnetic contribution was not considered in the present study, resulting in the omission of the S mag term in equation (5). The Gibbs free energy was determined from the Helmholtz free energy [33],…”

Section: Computation Detailsmentioning

confidence: 99%

“…Traditionally, density functional theory (DFT) calculations have long been used to successfully predict the ground-state structure and properties of simple single-phase systems [4][5][6]. However, attempts to analyze phase stability in multi-phase, multi-component materials with site disorders, as in MPCAs, using DFT-based methods are few and far between [7].…”

Section: Introductionmentioning

confidence: 99%

Understanding the phase stability in a multi-principal-component AlCuFeMn alloy

Swarnakar,

Ghosh,

Mahato

et al. 2024

J. Phys. D: Appl. Phys.

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Method(s) that can reliably predict phase evolution across thermodynamic parameter space, especially in complex systems are of critical significance in academia as well as in the manufacturing industry. In the present work, phase stability in equimolar AlCuFeMn multi-principal-component alloy (MPCA) was predicted using complementary first-principles density functional theory (DFT) calculations, and ab-initio molecular dynamics (AIMD) simulations. Temperature evolution of completely disordered, partially ordered, and completely ordered phases was examined based on Gibbs free energy. Configurational, electronic, vibrational, and lattice mismatch entropies were considered to compute the Gibbs free energy of the competing phases. Additionally, elemental segregation was studied using ab-initio molecular dynamics (AIMD). The predicted results at 300K align well with room-temperature experimental observations using x-ray diffraction, scanning and transmission electron microscopy on a sample prepared using commercially available pure elements. The adopted method could help in predicting plausible phases in other MPCA systems with complex phase stability.

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Towards quantifying (meta-)stability of multi-principal element alloys: From configurational entropy to characteristic temperatures

Zhang,

Dong,

Wang

et al. 2024

Acta Materialia

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Metastable high entropy alloys of TiZrHfTa with glass-like characteristics at low temperatures

Cited by 7 publications

References 38 publications

Towards quantifying (meta-)stability of multi-principal element alloys: from configurational entropy to characteristic temperatures

Towards quantifying (meta-)stability of multi-principal element alloys: from configurational entropy to characteristic temperatures

Understanding the phase stability in a multi-principal-component AlCuFeMn alloy

Towards quantifying (meta-)stability of multi-principal element alloys: From configurational entropy to characteristic temperatures

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