Mechanical properties of high-entropy alloys with emphasis on face-centered cubic 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

Microstructure and Mechanical Properties of the W-Ni-Co System Refractory High-Entropy Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.816.324 ◽

2015 ◽

Vol 816 ◽

pp. 324-329 ◽

Cited By ~ 3

Author(s):

Hui Jiang ◽

Li Jiang ◽

Yi Ping Lu ◽

Tong Min Wang ◽

Zhi Qiang Cao ◽

...

Keyword(s):

Mechanical Properties ◽

Vacuum Arc ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Melting Temperatures ◽

Arc Melting ◽

Microstructure And Mechanical Properties ◽

The Matrix ◽

Face Centered

The elements Mo, Cr and V were added to the W-Ni-Co system high entropy alloys, the effects of these added elements on microstructure and mechanical properties of these alloys were studied. The alloys were produced by vacuum arc melting. The compositions were W0.5Ni2Co2VMo0.5,W0.5Ni2Co2VCr0.5and W0.5Ni2Co2CrMo0.5(denoted as Alloy 1, Alloy 2 and Alloy 3) respectively. The theoretical melting temperatures were higher than 2000 K. X-ray diffraction, SEM and energy dispersive spectroscopy (EDS) results indicated that the matrix of the alloys is face-centered cubic (FCC) solid-solution, the alloys showed dendrite crystal structure. Ni, Co elements were enriched in the dendrite areas, the W, Mo were enriched in the inter-dendrite regions ,while V, Cr elements were uniform distribution. The Vickers hardness of these alloys was 376.1 HV, 255.88 HV and 306.8 HV, respectively. The yield strength values (σ0.2) of Alloy 1, Alloy 2 and Alloy 3 were approximately 1000MPa, 750MPa, 250MPa, respectively. The alloys show good compression plasticity deformation capacity at RT.

Download Full-text

Synergetic effect of Si addition on mechanical properties in face-centered-cubic high entropy alloys: A first-principles study

Modelling and Simulation in Materials Science and Engineering ◽

10.1088/1361-651x/ac455a ◽

2021 ◽

Author(s):

T Tsuru ◽

Ivan Lobzenko ◽

Daixiu Wei

Keyword(s):

Mechanical Properties ◽

First Principles ◽

Stacking Fault ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Si Doped ◽

Face Centered ◽

Si Addition ◽

Strength And Ductility

Abstract High-entropy alloys (HEA) have been receiving increased attention for their excellent mechanical properties. Our recent study revealed that Si-doped face-centered cubic (FCC) HEAs have great potential to improve both strength and ductility. Here, we carried out first-principles calculations in cooperation with Monte Carlo simulation and structural factor analysis to explore the effect of Si addition on the macroscopic mechanical properties. As a result, Si addition increased the local lattice distortion and the stacking fault energy. Furthermore, the short-range order formation in Si-doped alloy caused highly fluctuated stacking fault energy. Thus, the heterogeneous solid solution states in which low and high stacking fault regions are distributed into the matrix were nucleated. This unique feature in Si-doped FCC-HEA induces ultrafine twin formation in Si-doped alloys, which can be a dominant factor in improving both strength and ductility.

Download Full-text

Microstructure and Mechanical Properties of Face‐Centered‐Cubic‐Based Cr‐Free Equiatomic High‐Entropy Alloys

Advanced Engineering Materials ◽

10.1002/adem.202000848 ◽

2020 ◽

pp. 2000848

Author(s):

Xinwang Liu ◽

Peng Liu ◽

Weibin Zhang ◽

Qiang Hu ◽

Qiang Chen ◽

...

Keyword(s):

Mechanical Properties ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Microstructure And Mechanical Properties ◽

Face Centered

Download Full-text

Development of Novel Lightweight Al-Rich Quinary Medium-Entropy Alloys with High Strength and Ductility

Materials ◽

10.3390/ma14154223 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4223

Author(s):

Po-Sung Chen ◽

Yu-Chin Liao ◽

Yen-Ting Lin ◽

Pei-Hua Tsai ◽

Jason S. C. Jang ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Compressive Strain ◽

High Strength ◽

Fine Tuning ◽

Face Centered Cubic ◽

Transportation Industry ◽

High Entropy ◽

Good Potential ◽

Face Centered

Most high-entropy alloys and medium-entropy alloys (MEAs) possess outstanding mechanical properties. In this study, a series of lightweight nonequiatomic Al50–Ti–Cr–Mn–V MEAs with a dual phase were produced through arc melting and drop casting. These cast alloys were composed of body-centered cubic and face-centered cubic phases. The density of all investigated MEAs was less than 5 g/cm3 in order to meet energy and transportation industry requirements. The effect of each element on the microstructure evolution and mechanical properties of these MEAs was investigated. All the MEAs demonstrated outstanding compressive strength, with no fractures observed after a compressive strain of 20%. Following the fine-tuning of the alloy composition, the Al50Ti20Cr10Mn15V5 MEA exhibited the most compressive strength (~1800 MPa) and ductility (~34%). A significant improvement in the mechanical compressive properties was achieved (strength of ~2000 MPa, strain of ~40%) after annealing (at 1000 °C for 0.5 h) and oil-quenching. With its extremely high specific compressive strength (452 MPa·g/cm3) and ductility, the lightweight Al50Ti20Cr10Mn15V5 MEA demonstrates good potential for energy or transportation applications in the future.

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

Effect of Interstitial Elements on the Cryogenic Mechanical Behavior of FCC High Entropy Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.1386 ◽

2021 ◽

Vol 1016 ◽

pp. 1386-1391

Author(s):

Anastasia Semenyuk ◽

Margarita Klimova ◽

Sergey Zherebtsov ◽

Nikita Stepanov

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Thermomechanical Processing ◽

Induction Melting ◽

High Entropy Alloys ◽

Strengthening Effect ◽

Face Centered Cubic ◽

High Entropy ◽

C And N ◽

Interstitial Elements

High entropy alloys (HEAs) with face-centered cubic (fcc) structure, namely equiatomic CoCrFeMnNi alloy, have attracted considerable attention because of impressive cryogenic mechanical properties – strength, ductility, and fracture toughness. Further increase of the properties can be achieved, for example, by proper alloying. A particularly attractive option is the addition of interstitial elements like carbon or nitrogen. In present work, a series of CoCrFeMnNi-based alloys with different amounts of C and N (0-2 at.%) was prepared by induction melting. The alloys doped with C had lower Cr content to increase the solubility of carbon in the fcc solid solution. It was revealed that the solid solution strengthening effect of both C and N is significantly increased when the testing temperature decreases from 293K to 77K. The effect of thermomechanical processing on the structure and mechanical properties of the alloys is analyzed.

Download Full-text