scholarly journals The Exceptional Strong Face-centered Cubic Phase and Semi-coherent Phase Boundary in a Eutectic Dual-phase High Entropy Alloy AlCoCrFeNi

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Qiannan Wang ◽  
Yiping Lu ◽  
Qian Yu ◽  
Ze Zhang
Keyword(s):  
Phase Boundary ◽  
Cubic Phase ◽  
High Entropy Alloy ◽  
Dual Phase ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Coherent Phase ◽  
Face Centered

scholarly journals Magnetic and Transport Properties of New Dual-Phase High-Entropy Alloy FeRhIrPdPt

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2877
Author(s):  
Kohei Baba ◽  
Naoki Ishizu ◽  
Terukazu Nishizaki ◽  
Jiro Kitagawa
Keyword(s):  
Glass Transition ◽  
Transition Metals ◽  
Spin Glass ◽  
Transport Properties ◽  
High Entropy Alloy ◽  
Dual Phase ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Spin Glass Transition ◽  
Face Centered

High-entropy alloys (HEAs) are broadly explored from the perspective of mechanical, corrosion-resistance, catalytic, structural, superconducting, magnetic properties, and so on. In magnetic HEAs, 3d transition metals or rare-earth elements are well-studied compositional elements. We researched a magnetic HEA containing Fe combined with 4d and 5d transition metals, which has not been well investigated, and found a new dual-phase face-centered-cubic (fcc) HEA FeRhIrPdPt. The structural, magnetic, and transport properties were evaluated by assuming that FeRhIrPdPt is a mixture of FeRh4, FeIr4, FePd4, and FePt4, all with the fcc structure. The dual-phase is composed of a Rh- and Ir-rich main phase and a Pd- and Pt-rich minor one. FeRh4 and FeIr4 show spin freezings at low temperatures, while FePd4 and FePt4 are ferromagnetic. Two magnetic features can characterize FeRhIrPdPt. One is the canonical spin-glass transition at 90 K, and the other is a ferromagnetic correlation that appears below 300 K. The main and minor phases were responsible for the spin-glass transition and the ferromagnetic correlation below 300 K, respectively.

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 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.

Vanishing of room-temperature slip avalanches in a face-centered-cubic high-entropy alloy by ultrafine grain formation

2018 ◽  
Vol 155 ◽  
pp. 99-103 ◽  
Author(s):  
Jian Qiang ◽  
Koichi Tsuchiya ◽  
Haoyan Diao ◽  
Peter K. Liaw
Keyword(s):  
Room Temperature ◽  
Ultrafine Grain ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Grain Formation ◽  
Face Centered

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

scholarly journals Effect of Mn Addition on the Microstructures and Mechanical Properties of CoCrFeNiPd High Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 288
Author(s):  
Yiming Tan ◽  
Jinshan Li ◽  
Jun Wang ◽  
Hongchao Kou
Keyword(s):  
Intermetallic Compound ◽  
Interface Energy ◽  
High Entropy Alloy ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
Liquid Interfaces ◽  
High Entropy ◽  
Single Face ◽  
Face Centered ◽  
Fcc Phase

CoCrFeNiPdMnx (x = 0, 0.2, 0.4, 0.6, 0.8) high entropy alloys (HEAs) were prepared and characterized. With an increase in Mn addition, the microstructures changed from dendrites (CoCrFeNiPd with a single face-centered-cubic (FCC) phase) to divorced eutectics (CoCrFeNiPdMn0.2 and CoCrFeNiPdMn0.4), to hypoeutectic microstructures (CoCrFeNiPdMn0.6), and finally to seaweed eutectic dendrites (CoCrFeNiPdMn0.8). The addition of Mn might change the interface energy anisotropy of both the FCC/liquid and MnPd-rich intermetallic compound/liquid interfaces, thus forming the seaweed eutectic dendrites. The hardness of the FCC phase was found to be highly related to the solute strengthening effect, the formation of nanotwins and the transition from CoCrFeNiPd-rich to CoCrFeNi-rich FCC phase. Hierarchical nanotwins were found in the MnPd-rich intermetallic compound and a decrease in either the spacing of primary twins or secondary twins led to an increase in hardness. The designing rules of EHEAs were discussed and the pseudo binary method was revised accordingly.

Tension/compression asymmetry in additive manufactured face centered cubic high entropy alloy

2017 ◽  
Vol 129 ◽  
pp. 30-34 ◽  
Author(s):  
Jithin Joseph ◽  
Nicole Stanford ◽  
Peter Hodgson ◽  
Daniel Mark Fabijanic
Keyword(s):  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Face Centered ◽  
Tension Compression Asymmetry

scholarly journals Materials Research on High-Entropy Alloy Superconductors

2021 ◽  
Author(s):  
Jiro Kitagawa ◽  
Naoki Ishizu ◽  
Shusuke Hamamoto
Keyword(s):  
Valence Electron ◽  
Superconducting Property ◽  
Hexagonal Structure ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Materials Research ◽  
Face Centered ◽  
Multi Phase ◽  
High Degree

The first purpose of this chapter is materials research on face-centered-cubic (fcc) high-entropy alloy (HEA) superconductors, which have not yet been reported. We have investigated several Nb-containing multicomponent alloys. Although we succeeded in obtaining Nb-containing samples with the dominant fcc phases, no superconducting signals appeared in these samples down to 3 K. The microstructure analyses revealed that all samples were multi-phase, but the existence of several new Nb-containing HEA phases was confirmed in them. The second purpose is the report of materials research on the Mn5Si3-type HEA superconductors. This hexagonal structure offers various intermetallic compounds, which often undergo a superconducting state. The Mn5Si3-type HEA is classified into the multisite HEA, which possesses the high degree of freedom in the materials design and is good platform for studying exotic HEA superconductors. We have successfully found a single-phase Mn5Si3-type HEA, which, however, does not show a superconducting property down to 3 K. The attempt of controlling the valence electron count was not successful.

scholarly journals A novel face-centered-cubic high-entropy alloy strengthened by nanoscale precipitates

2019 ◽  
Vol 172 ◽  
pp. 51-55 ◽  
Author(s):  
Gang Qin ◽  
Ruirun Chen ◽  
Peter K. Liaw ◽  
Yanfei Gao ◽  
Xiaoqing Li ◽  
...  
Keyword(s):  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Face Centered
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