scholarly journals Unconventional Deformation Behaviours of Nanoscaled High-Entropy Alloys

Entropy ◽  
2018 ◽  
Vol 20 (10) ◽  
pp. 778 ◽  
Author(s):  
Yeqiang Bu ◽  
Shenyou Peng ◽  
Shiwei Wu ◽  
Yujie Wei ◽  
Gang Wang ◽  
...  
Keyword(s):  
Phase Transformations ◽  
First Principles ◽  
Atomic Scale ◽  
High Entropy Alloys ◽  
First Principles Calculations ◽  
High Entropy ◽  
Fcc Metals ◽  
The Stability ◽  
Similar Deformation

The bulk high-entropy alloys (HEAs) exhibit similar deformation behaviours as traditional metals. These bulk behaviours are likely an averaging of the behaviours exhibited at the nanoscale. Herein, in situ atomic-scale observation of deformation behaviours in nanoscaled CoCrCuFeNi face-centred cubic (FCC) HEA was performed. The deformation behaviours of this nanoscaled FCC HEA (i.e., nanodisturbances and phase transformations) were distinct from those of nanoscaled traditional FCC metals and corresponding bulk HEA. First-principles calculations revealed an obvious fluctuation of the stacking fault energy and stability difference at the atomic scale in the HEA. The stability difference was highlighted only in the nanoscaled HEA and induced unconventional deformation behaviours. Our work suggests that the nanoscaled HEA may provide more chances to discover the long-expected essential distinction between the HEAs and traditional metals.

scholarly journals High-Pressure Induced Phase Transitions in High-Entropy Alloys: A Review

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 239 ◽  
Author(s):  
Fei Zhang ◽  
Hongbo Lou ◽  
Benyuan Cheng ◽  
Zhidan Zeng ◽  
Qiaoshi Zeng
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Future Research ◽  
High Entropy Alloys ◽  
High Entropy ◽  
New Class ◽  
Materials Research ◽  
The Stability ◽  
Irreversible Phase Transitions

High-entropy alloys (HEAs) as a new class of alloy have been at the cutting edge of advanced metallic materials research in the last decade. With unique chemical and topological structures at the atomic level, HEAs own a combination of extraordinary properties and show potential in widespread applications. However, their phase stability/transition, which is of great scientific and technical importance for materials, has been mainly explored by varying temperature. Recently, pressure as another fundamental and powerful parameter has been introduced to the experimental study of HEAs. Many interesting reversible/irreversible phase transitions that were not expected or otherwise invisible before have been observed by applying high pressure. These recent findings bring new insight into the stability of HEAs, deepens our understanding of HEAs, and open up new avenues towards developing new HEAs. In this paper, we review recent results in various HEAs obtained using in situ static high-pressure synchrotron radiation x-ray techniques and provide some perspectives for future research.

The stability of B6 octahedron in BaB6 under high pressure

RSC Advances ◽  
2016 ◽  
Vol 6 (22) ◽  
pp. 18077-18081 ◽  
Author(s):  
Xin Li ◽  
Xiaoli Huang ◽  
Defang Duan ◽  
Gang Wu ◽  
Mingkun Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
First Principles ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
Compression Behavior ◽  
X Ray ◽  
The Stability

We have performed in situ synchrotron X-ray diffraction and first-principles calculations to explore the compression behavior of barium hexaboride (BaB6) under high pressure.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

scholarly journals Anion ordering and vacancy defects in niobium perovskite oxynitrides

2021 ◽  
Vol 2 (7) ◽  
pp. 2398-2407
Author(s):  
Joshua J. Brown ◽  
Youxiang Shao ◽  
Zhuofeng Ke ◽  
Alister J. Page
Keyword(s):  
First Principles ◽  
First Principles Calculations ◽  
Defect Engineering ◽  
Vacancy Defects ◽  
The Stability

First-principles calculations predict the stability and mobility of vacancy defects in niobium perovskite oxynitrides, aiding defect engineering for enhanced photocatalysis.

Sign in / Sign up

Export Citation Format

Share Document