scholarly journals TiCoCrFeMn (BCC + C14) High-Entropy Alloy Multiphase Structure Analysis Based on the Theory of Molecular Orbitals

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5285
Author(s):  
Dominika Gorniewicz ◽  
Hubert Przygucki ◽  
Mateusz Kopec ◽  
Krzysztof Karczewski ◽  
Stanisław Jóźwiak
Keyword(s):  
Phase Structure ◽  
Average Energy ◽  
Molecular Orbitals ◽  
The Body ◽  
Design Stage ◽  
Orbital Parameter ◽  
High Entropy Alloy ◽  
Powder Metallurgy Method ◽  
High Entropy ◽  
Electron Microscopy Analysis

High-entropy alloys (HEA) are a group of modern, perspective materials that have been intensively developed in recent years due to their superior properties and potential applications in many fields. The complexity of their chemical composition and the further interactions of main elements significantly inhibit the prediction of phases that may form during material processing. Thus, at the design stage of HEA fabrication, the molecular orbitals theory was proposed. In this method, the connection of the average strength of covalent bonding between the alloying elements (Bo parameter) and the average energy level of the d-orbital (parameter Md) enables for a preliminary assessment of the phase structure and the type of lattice for individual components in the formed alloy. The designed TiCoCrFeMn alloy was produced by the powder metallurgy method, preceded by mechanical alloying of the initial elementary powders and at the temperature of 1050 °C for 60 s. An ultra-fine-grained structured alloy was homogenized at 1000 °C for 1000 h. The X-ray diffraction and scanning electron microscopy analysis confirmed the correctness of the methodology proposed as the assumed phase structure consisted of the body-centered cubic (BCC) solid solution and the C14 Laves phase was obtained.

Novel Fe36Mn21Cr18Ni15Al10 high entropy alloy with bcc/B2 dual-phase structure

2017 ◽  
Vol 705 ◽  
pp. 756-763 ◽  
Author(s):  
D.G. Shaysultanov ◽  
G.A. Salishchev ◽  
Yu.V. Ivanisenko ◽  
S.V. Zherebtsov ◽  
M.A. Tikhonovsky ◽  
...  
Keyword(s):  
Phase Structure ◽  
High Entropy Alloy ◽  
Dual Phase ◽  
High Entropy

scholarly journals Structural and Thermodynamic Properties of the High-Entropy Alloy AlCoCrFeNi Based on First-Principles Calculations

2020 ◽  
Vol 7 ◽  
Author(s):  
Juefei Wu ◽  
Zhen Yang ◽  
Jiawei Xian ◽  
Xingyu Gao ◽  
Deye Lin ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
High Pressures ◽  
Dynamic Properties ◽  
Field Potential ◽  
The Body ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Local Lattice Distortion ◽  
High Entropy

During the past two decades, the high-entropy alloy AlCoCrFeNi has attracted much attention due to its outstanding thermal and mechanical properties under ambient conditions. However, the exploration on the thermodynamic properties of this alloy under high temperatures and high pressures is relatively insufficient. Combining structural modeling with the similar atomic environment (SAE) method and first-principles simulations with the modified mean-field potential (MMFP) approach, we studied the lattice and magnetic structure as well as the thermodynamic properties of the body-centered-cubic AlCoCrFeNi, through supercell simulations. AlCoCrFeNi was found to display a strong local lattice distortion compared with typical 3d high-entropy alloys; the ferromagnetic structure stable at 0 K was predicted to transform to the paramagnetic structure at the Curie temperature TC = 279.75 K, in good agreement with previous calculations; the calculated equilibrium volumes, bulk modulus, and shock Hugoniot all agree well with available experimental data and other theoretical values. These results demonstrate the validity and reliability of our methods used to study the dynamic properties of AlCoCrFeNi, providing a promising scheme for accessing the dynamic properties of sophisticated high-entropy alloys.

scholarly journals Effect of Enhanced Gravity on the Microstructure and Mechanical Properties of Al0.9CoCrFeNi High-Entropy Alloy

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1318
Author(s):  
Anjun Shi ◽  
Ruixuan Li ◽  
Yong Zhang ◽  
Zhe Wang ◽  
Zhancheng Guo
Keyword(s):  
Mechanical Properties ◽  
The Body ◽  
Grain Structure ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Microstructure And Mechanical Properties ◽  
Gravity Fields ◽  
Bcc Structure ◽  
Strength And Plasticity ◽  
Gravity Acceleration

The influence of enhanced gravity on the microstructure and mechanical properties of the Al0.9CoCrFeNi high-entropy alloy, which was solidified under normal gravity (acceleration 1 g) and enhanced gravity (acceleration 140 g, acceleration 210 g, and acceleration 360 g) conditions is reported in this paper. Its solidification under enhanced gravity fields resulted in refinement of the columnar nondendritic grain structure and an increase in the area fraction of the body-centered cubic (BCC) structure phases. The mass transfer strengthened by enhanced gravity promoted element diffusion and enrichment, which caused changes in the composition and microstructure that, in turn, affected the mechanical properties of the alloy. The compressive strength and plasticity of the sample solidified at acceleration 360 g were equal to 2845 MPa and 36.4%, respectively, which are the highest values reported to date for Al0.9CoCrFeNi alloy.

Fabrication of in-situ TiN ceramic particle reinforced high entropy alloy composite coatings by laser cladding processing

2021 ◽  
pp. 1-22
Author(s):  
Xinhong Wang ◽  
S. S. Liu ◽  
G. L. Zhao ◽  
M. Zhang
Keyword(s):  
Laser Cladding ◽  
Phase Structure ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Ceramic Particle ◽  
304 Stainless Steel ◽  
High Entropy Alloy ◽  
Laves Phases ◽  
High Entropy

Abstract In-situ TiN ceramic particle reinforced FeCoNiCrMnTi high entropy alloy coating was fabricated by laser cladding processing at high purity nitrogen gas atmosphere on the AISI 304 stainless steel substrate. The effect of Ti addition on the microstructure, phase structure and wear properties of the coatings were investigated. The results showed that phase structure of the coatings were mainly FCC-type γ phase. A few of cubic or flower-like TiN ceramic were formed after adding titanium into the FeCoNiCrMn powder. When atomic ratio of Ti exceeds 0.5, Laves phases appeared in the coatings. With increasing of Ti, the micro-hardness and wear resistance of the coatings increased, but friction coefficient and crack resistance of the coatings reduced. Suitable Ti content in the FeCoNiCrMnTix, laser composite coating had higher resistance to adhesive wear, oxidation wear and cracking resistance.

Preparation of CoCrFeNiCuMnSix High Entropy Alloys and their Microstructure and Properties

2013 ◽  
Vol 750-752 ◽  
pp. 615-618 ◽  
Author(s):  
Li Sheng Zhang
Keyword(s):  
Phase Structure ◽  
Optical Microscope ◽  
Vacuum Arc ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Dendrite Morphology ◽  
High Entropy ◽  
Bcc Structure ◽  
Si Content ◽  
Cast Microstructure

According to the design concept of multi-element high-entropy alloys, seven kinds of elements (Cr, Mn, Fe, Co, Ni, Cu and Si) were selected in this work to design a series of CoCrFeNiCuMnSix high entropy alloys. Metal power was melted by vacuum arc furnace. Cast microstructure and phase structure of the high entropy alloy were Characterized by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD). And then, hardness, wear resistance and corrosion resistance were tested. Phase structure of cast microstructure, the morphology of the microstructure and mechanical properties of the CoCrFeNiCuMnSix high entropy alloys were researched systematic in the condition of different content Si. The results show that the crystal structure is simple BCC structure. With the increasing Si content, the alloy cast structure changes from dendrite morphology to cellular morphology. It was Si content that plays an important role in increasing significantly the hardness of the alloy. The hardness of the maximum value reaches to HV985.

Effect of Cold Rolling on the Microstructure and Hardness of Al5Cr12Fe35Mn28Ni20 High Entropy Alloy

2018 ◽  
Vol 917 ◽  
pp. 241-245 ◽  
Author(s):  
Sally Elkatatny ◽  
Mohamed Abdel Hady Gepreel ◽  
Atef Hamada
Keyword(s):  
Cold Rolling ◽  
Phase Structure ◽  
Rolling Reduction ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Characterization Methods ◽  
High Entropy ◽  
Cold Rolling Reduction ◽  
Fcc Phase ◽  
Dendritic Structures

The microstructure and hardness changes of a non-equiatomic Al5Cr12Fe35Mn28Ni20high-entropy-alloys (HEA) with cold rolling are presented here. Using a variety of characterization methods, it is shown that the alloy is single FCC phase structure which doesn't change with cold rolling up to90%CR. With increasing the cold rolling reduction ratio, the hardness increased and the dendritic structures are broken and refined.

The Study about Microstructure Characterization of AlCoCrTiNiCu_x High Entropy Alloy System with Multi-Principal Element

2011 ◽  
Vol 399-401 ◽  
pp. 3-7 ◽  
Author(s):  
Chun Wei Wang ◽  
Zhuo Qiang Mo ◽  
Jian Jiang Tang
Keyword(s):  
Crystal Structure ◽  
Transition Metal ◽  
Change Process ◽  
Phase Structure ◽  
Alloy System ◽  
High Entropy Alloy ◽  
Principal Element ◽  
High Entropy ◽  
Metal Elements

The microstructure and phase structure of AlCoCrTiNiCu_x which are made of six class transition metal elements have been studied in this paper. The results indicated that the change process of microcosmic crystal-structure of the five group high entropy alloy of AlCoCrTiNiCu_x system is transformed from FCC（mainly）+ BCC crystal structure (X=0.5、X=0.8) to FCC+BCC+ primary lattice crystal structure (X=1.0、X=1.2), finally, the crystal-structure turn into BCC+ primary lattice crystal structure as the content of Cu further increasing.

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