Bimodality of incipient plastic strength in face-centered cubic high-entropy alloys

The structural stability of high-entropy alloys (HEAs) is closely related to their mechanical properties. The precise control of the component content is a key step toward understanding their structural stability and further determining their mechanical properties. In this study, first-principle calculations were performed to investigate the effects of different contents of each component on the structural stability and mechanical properties of Co-Cr-Fe-Ni HEAs based on the supercell model. Co-Cr-Fe-Ni HEAs were constructed based on a single face-centered cubic (FCC) solid solution. Elemental components have a clear effect on their structure and performance; the Cr and Fe elements have an obvious effect on the structural stability and equilibrium lattice constant, respectively. The Ni elements have an obvious effect on stiffness. The Pugh ratios indicate that Cr and Ni addition may increase ductility, whereas Co and Fe addition may decrease it. With increasing Co and Fe contents or decreasing Cr and Ni contents, the structural stability and stiffness of Co-Cr-Fe-Ni HEAs are improved. The structural stability and mechanical properties may be related to the strength of the metallic bonding and covalent bonding inside Co-Cr-Fe-Ni HEAs, which, in turn, is determined by the change in element content. Our results provide the underlying insights needed to guide the optimization of Co-Cr-Fe-Ni HEAs with excellent mechanical properties.

Download Full-text

Insights into Defect-Mediated Nucleation of Equilibrium B2 Phase in Face-Centered Cubic High-Entropy Alloys

JOM ◽

10.1007/s11837-021-04754-3 ◽

2021 ◽

Author(s):

Abhishek Sharma ◽

Bharat Gwalani ◽

Sriswaroop Dasari ◽

Deep Choudhuri ◽

Yao-Jen Chang ◽

...

Keyword(s):

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

B2 Phase ◽

Face Centered

Download Full-text

Micro-compression studies of face-centered cubic and body-centered cubic high-entropy alloys: Size-dependent strength, strain rate sensitivity, and activation volumes

Materials Science and Engineering A ◽

10.1016/j.msea.2020.139429 ◽

2020 ◽

Vol 790 ◽

pp. 139429 ◽

Cited By ~ 4

Author(s):

Yuan Xiao ◽

Roksolana Kozak ◽

Michel J.R. Haché ◽

Walter Steurer ◽

Ralph Spolenak ◽

...

Keyword(s):

Strain Rate ◽

Strain Rate Sensitivity ◽

Rate Sensitivity ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

Body Centered Cubic ◽

High Entropy ◽

Size Dependent ◽

Face Centered

Download Full-text

Effects of Mn Content and Grain Size on Hydrogen Embrittlement Susceptibility of Face-Centered Cubic High-Entropy Alloys

Metallurgical and Materials Transactions A ◽

10.1007/s11661-020-05966-z ◽

2020 ◽

Vol 51 (11) ◽

pp. 5612-5616

Author(s):

Motomichi Koyama ◽

Haoyu Wang ◽

Virendra Kumar Verma ◽

Kaneaki Tsuzaki ◽

Eiji Akiyama

Keyword(s):

Grain Size ◽

Hydrogen Embrittlement ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Mn Content ◽

Face Centered

Download Full-text

Metalloid substitution elevates simultaneously the strength and ductility of face-centered-cubic high-entropy alloys

Acta Materialia ◽

10.1016/j.actamat.2021.117571 ◽

2021 ◽

pp. 117571

Author(s):

Daixiu Wei ◽

Liqiang Wang ◽

Yongjie Zhang ◽

Wu Gong ◽

Tomohito Tsuru ◽

...

Keyword(s):

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Face Centered ◽

Strength And Ductility

Download Full-text

Effect of Molybdenum Additives on Corrosion Behavior of (CoCrFeNi)100−xMox High-Entropy Alloys

Entropy ◽

10.3390/e20120908 ◽

2018 ◽

Vol 20 (12) ◽

pp. 908 ◽

Cited By ~ 9

Author(s):

Wenrui Wang ◽

Jieqian Wang ◽

Honggang Yi ◽

Wu Qi ◽

Qing Peng

Keyword(s):

Corrosion Behavior ◽

Compressive Strain ◽

Compressive Yield Strength ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

Σ Phase ◽

High Entropy ◽

Passivation Film ◽

Face Centered ◽

Mo Content

The present work investigates the influence of micro-alloyed Mo on the corrosion behavior of (CoCrFeNi)100−xMox high-entropy alloys. All of the (CoCrFeNi)100−xMox alloys exhibit a single face-centered cubic (FCC) solid solution. However, the (CoCrFeNi)97Mo3 alloy exhibits an ordered sigma (σ) phase enriched in Cr and Mo. With the increase of x (the Mo content) from 1 to 3, the hardness of the (CoCrFeNi)100−xMox alloys increases from 124.8 to 133.6 Vickers hardness (HV), and the compressive yield strength increases from 113.6 MPa to 141.1 MPa, without fracture under about a 60% compressive strain. The potentiodynamic polarization curve in a 3.5% NaCl solution indicates that the addition of Mo has a beneficial effect on the corrosion resistance to some certain extent, opposed to the σ phase. Furthermore, the alloys tend to form a passivation film in the 0.5 M H2SO4 solution in order to inhibit the progress of the corrosion reaction as the Mo content increases.

Download Full-text

Magnetic Properties and Microstructure of FeCoNi(CuAl)0.8Snx (0 ≤ x ≤ 0.10) High-Entropy Alloys

Entropy ◽

10.3390/e20110872 ◽

2018 ◽

Vol 20 (11) ◽

pp. 872 ◽

Cited By ~ 8

Author(s):

Zhong Li ◽

Chenxu Wang ◽

Linye Yu ◽

Yong Gu ◽

Minxiang Pan ◽

...

Keyword(s):

Magnetic Properties ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Tc ◽

Soft Magnets ◽

High Entropy ◽

Face Centered ◽

Fcc Phase ◽

Bcc Phase ◽

Curie Temperatures

The present work exhibits the effects of Sn addition on the magnetic properties and microstructure of FeCoNi(CuAl)0.8Snx (0 ≤ x ≤ 0.10) high-entropy alloys (HEAs). The results show all the samples consist of a mixed structure of face-centered-cubic (FCC) phase and body-centered-cubic (BCC) phase. The addition of Sn promotes the formation of BCC phase, and it also affects the shape of Cu-rich nano-precipitates in BCC matrix. It also shows that the Curie temperatures (Tc) of the FCC phase and the saturation magnetization (Ms) of the FeCoNi(CuAl)0.8Snx (0 ≤ x ≤ 0.10) HEAs increase greatly while the remanence (Br) decreases after the addition of Sn into FeCoNi(CuAl)0.8 HEA. The thermomagnetic curves indicate that the phases of the FeCoNi(CuAl)0.8Snx (0 ≤ x ≤ 0.10) HEAs will transform from FCC with low Tc to BCC phase with high Tc at temperature of 600–700 K. This work provides a new idea for FeCoNi(CuAl)0.8Snx (0 ≤ x ≤ 0.10) HEAs for their potential application as soft magnets to be used at high temperatures.

Download Full-text

Influence of Ti on the Tensile Properties of the High-Strength Powder Metallurgy High Entropy Alloys

Materials ◽

10.3390/ma13030578 ◽

2020 ◽

Vol 13 (3) ◽

pp. 578 ◽

Cited By ~ 3

Author(s):

Igor Moravcik ◽

Stepan Gamanov ◽

Larissa Moravcikova-Gouvea ◽

Zuzana Kovacova ◽

Michael Kitzmantel ◽

...

Keyword(s):

Powder Metallurgy ◽

Tensile Properties ◽

High Strength ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Solid Solution Strengthening ◽

Plasma Sintering ◽

Annealing Heat Treatment ◽

Face Centered

The focus of this study is the evaluation of the influence of Ti concentration on the tensile properties of powder metallurgy high entropy alloys. Three Ni1.5Co1.5CrFeTiX alloys with X = 0.3; 0.5 and 0.7 were produced by mechanical alloying and spark plasma sintering. Additional annealing heat treatment at 1100 °C was utilized to obtain homogenous single-phase face centered cubic (FCC) microstructures, with minor oxide inclusions. The results show that Ti increases the strength of the alloys by increasing the average atomic size misfit i.e., solid solution strengthening. An excellent combination of mechanical properties can be obtained by the proposed method. For instance, annealed Ni1,5Co1,5CrFeTi0.7 alloy possessed the ultimate tensile strength as high as ~1600 MPa at a tensile ductility of ~9%, despite the oxide contamination. The presented results may serve as a guideline for future alloy design of novel, inclusion-tolerant materials for sustainable metallurgy.

Download Full-text

Ultrastrong Al0.1CoCrFeNi high-entropy alloys at small scales: effects of stacking faults vs. nanotwins

Nanoscale ◽

10.1039/c8nr03573c ◽

2018 ◽

Vol 10 (28) ◽

pp. 13329-13334 ◽

Cited By ~ 19

Author(s):

Xiaobin Feng ◽

Jinyu Zhang ◽

Kai Wu ◽

Xiaoqing Liang ◽

Gang Liu ◽

...

Keyword(s):

Stacking Faults ◽

Maximum Strength ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Small Scales ◽

Face Centered

The present stacking faulted and nanotwinned Al0.1CoCrFeNi high-entropy alloy pillars achieved the maximum strength among face-centered cubic structured metals.

Download Full-text