Atomistic Simulations of the Face-Centered-Cubic-To-Hexagonal-Close-Packed Phase Transformation in the Equiatomic CoCrFeMnNi High Entropy Alloy Under High Compression

2019 ◽  
Author(s):  
Kang-Tien Hsieh ◽  
You-Yi Lin ◽  
Chi-Hung Lu ◽  
Jer-Ren Yang ◽  
Peter K. Liaw ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Atomistic Simulations ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hexagonal Close Packed ◽  
High Compression ◽  
The Face ◽  
Face Centered

scholarly journals Microstructure Refinement by Low-Temperature Ausforming in an Fe-Based Metastable High-Entropy Alloy

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 742
Author(s):  
Motomichi Koyama ◽  
Takeaki Gondo ◽  
Kaneaki Tsuzaki
Keyword(s):  
Low Temperature ◽  
Plastic Anisotropy ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Microstructure Refinement ◽  
Hexagonal Close Packed ◽  
Solution Treated Condition ◽  
Solution Treated ◽  
Face Centered

The effects of ausforming in an Fe30Mn10Cr10Co high-entropy alloy on the microstructure, hardness, and plastic anisotropy were investigated. The alloy showed a dual-phase microstructure consisting of face-centered cubic (FCC) austenite and hexagonal close-packed (HCP) martensite in the as-solution-treated condition, and the finish temperature for the reverse transformation was below 200 °C. Therefore, low-temperature ausforming at 200 °C was achieved, which resulted in microstructure refinement and significantly increased the hardness. Furthermore, plasticity anisotropy, a common problem in HCP structures, was suppressed by the ausforming treatment. This, in turn, reduced the scatter of the hardness.

scholarly journals Microstructure, Texture, and Strength Development during High-Pressure Torsion of CrMnFeCoNi High-Entropy Alloy

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 336 ◽  
Author(s):  
Werner Skrotzki ◽  
Aurimas Pukenas ◽  
Eva Odor ◽  
Bertalan Joni ◽  
Tamas Ungar ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Strength Development ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
X Ray ◽  
High Entropy ◽  
Face Centered

The equiatomic face-centered cubic high-entropy alloy CrMnFeCoNi was severely deformed at room and liquid nitrogen temperature by high-pressure torsion up to shear strains of about 170. Its microstructure was analyzed by X-ray line profile analysis and transmission electron microscopy and its texture by X-ray microdiffraction. Microhardness measurements, after severe plastic deformation, were done at room temperature. It is shown that at a shear strain of about 20, a steady state grain size of 24 nm, and a dislocation density of the order of 1016 m−2 is reached. The dislocations are mainly screw-type with low dipole character. Mechanical twinning at room temperature is replaced by a martensitic phase transformation at 77 K. The texture developed at room temperature is typical for sheared face-centered cubic nanocrystalline metals, but it is extremely weak and becomes almost random after high-pressure torsion at 77 K. The strength of the nanocrystalline material produced by high-pressure torsion at 77 K is lower than that produced at room temperature. The results are discussed in terms of different mechanisms of deformation, including dislocation generation and propagation, twinning, grain boundary sliding, and phase transformation.

Phase transformation assisted twinning in a face-centered-cubic FeCrNiCoAl high entropy alloy

2019 ◽  
Vol 181 ◽  
pp. 491-500 ◽  
Author(s):  
Peijun Yu ◽  
Rui Feng ◽  
Junping Du ◽  
Shuhei Shinzato ◽  
Jyh-Pin Chou ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Face Centered

scholarly journals Vacuum brazing of Al2O3 and 3D printed Ti6Al4V lap-joints using high entropy driven AlZnCuFeSi filler

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ashutosh Sharma ◽  
Byungmin Ahn
Keyword(s):  
Strength Properties ◽  
Lap Joints ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
3D Printed ◽  
Face Centered ◽  
Alloy Filler

AbstractIn this work, we studied the brazing characteristics of Al2O3 and 3D printed Ti–6Al–4V alloys using a novel equiatomic AlZnCuFeSi high entropy alloy filler (HEAF). The HEAF was prepared by mechanical alloying of the constituent powder and spark plasma sintering (SPS) approach. The filler microstructure, wettability and melting point were investigated. The mechanical and joint strength properties were also evaluated. The results showed that the developed AlZnCuFeSi HEAF consists of a dual phase (Cu–Zn, face-centered cubic (FCC)) and Al–Fe–Si rich (base centered cubic, BCC) phases. The phase structure of the (Cu–Al + Ti–Fe–Si)/solid solution promises a robust joint between Al2O3 and Ti–6Al–4V. In addition, the joint interfacial reaction was found to be modulated by the brazing temperature and time because of the altered activity of Ti and Zn. The optimum shear strength reached 84 MPa when the joint was brazed at 1050 °C for 60 s. The results can be promising for the integration of completely different materials using the entropy driven fillers developed in this study.

scholarly journals Cutting Edge of High-Entropy Alloy Superconductors from the Perspective of Materials Research

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1078
Author(s):  
Jiro Kitagawa ◽  
Shusuke Hamamoto ◽  
Naoki Ishizu
Keyword(s):  
Material Design ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Simple Material ◽  
Σ Phase ◽  
High Entropy ◽  
Cscl Type ◽  
Materials Research ◽  
Face Centered ◽  
New Phenomena

High-entropy alloys (HEAs) are a new class of materials which are being energetically studied around the world. HEAs are characterized by a multicomponent alloy in which five or more elements randomly occupy a crystallographic site. The conventional HEA concept has developed into simple crystal structures such as face-centered-cubic (fcc), body-centered-cubic (bcc) and hexagonal-closed packing (hcp) structures. The highly atomic-disordered state produces many superior mechanical or thermal properties. Superconductivity has been one of the topics of focus in the field of HEAs since the discovery of the bcc HEA superconductor in 2014. A characteristic of superconductivity is robustness against atomic disorder or extremely high pressure. The materials research on HEA superconductors has just begun, and there are open possibilities for unexpectedly finding new phenomena. The present review updates the research status of HEA superconductors. We survey bcc and hcp HEA superconductors and discuss the simple material design. The concept of HEA is extended to materials possessing multiple crystallographic sites; thus, we also introduce multisite HEA superconductors with the CsCl-type, α-Mn-type, A15, NaCl-type, σ-phase and layered structures and discuss the materials research on multisite HEA superconductors. Finally, we present the new perspectives of eutectic HEA superconductors and gum metal HEA superconductors.

scholarly journals Dynamic deformation behavior of a face-centered cubic FeCoNiCrMn high-entropy alloy

2018 ◽  
Vol 63 (6) ◽  
pp. 362-368 ◽  
Author(s):  
Junyang He ◽  
Qi Wang ◽  
Husheng Zhang ◽  
Lanhong Dai ◽  
Toshiji Mukai ◽  
...  
Keyword(s):  
Deformation Behavior ◽  
Dynamic Deformation ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Dynamic Deformation Behavior ◽  
Face Centered
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