scholarly journals The Evolution of Intermetallic Compounds in High-Entropy Alloys: From the Secondary Phase to the Main Phase

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2054
Author(s):  
Junqi Liu ◽  
Xiaopeng Wang ◽  
Ajit Singh ◽  
Hui Xu ◽  
Fantao Kong ◽  
...  
Keyword(s):  
Solid Solution ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
High Performance ◽  
Single Phase ◽  
Secondary Phase ◽  
Main Phase ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
High Entropy

High-performance structural materials are critical to the development of transportation, energy, and aerospace. In recent years, newly developed high-entropy alloys with a single-phase solid-solution structure have attracted wide attention from researchers due to their excellent properties. However, this new material also has inevitable shortcomings, such as brittleness at ambient temperature and thermodynamic instability at high temperature. Efforts have been made to introduce a small number of intermetallic compounds into single-phase solid-solution high-entropy alloys as a secondary phase to their enhance properties. Various studies have suggested that the performance of high-entropy alloys can be improved by introducing more intermetallic compounds. At that point, researchers designed an intermetallic compound-strengthened high-entropy alloy, which introduced a massive intermetallic compound as a coherent strengthening phase to further strengthen the matrix of the high-entropy alloy. Inspired from this, Fantao obtained a new alloy—high-entropy intermetallics—by introducing different alloying elements to multi-principalize the material in a previous study. This new alloy treats the intermetallic compound as the main phase and has advantages of both structural and functional materials. It is expected to become a new generation of high-performance amphibious high-entropy materials across the field of structure and function. In this review, we first demonstrate the inevitability of intermetallic compounds in high-entropy alloys and explain the importance of intermetallic compounds in improving the properties of high-entropy alloys. Secondly, we introduce two new high-entropy alloys mainly from the aspects of composition design, structure, underlying mechanism, and performance. Lastly, the high-entropy materials containing intermetallic compound phases are summarized, which lays a theoretical foundation for the development of new advanced materials.

A review on phase prediction in high entropy alloys

2021 ◽  
pp. 095440622110089
Author(s):  
Vinay Kumar Soni ◽  
S Sanyal ◽  
K Raja Rao ◽  
Sudip K Sinha
Keyword(s):  
Solid Solution ◽  
Phase Formation ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Modeling Tools ◽  
High Entropy ◽  
Recent Developments ◽  
Phase Prediction ◽  
The Stability

The formation of single phase solid solution in High Entropy Alloys (HEAs) is essential for the properties of the alloys therefore, numerous approach were proposed by many researchers to predict the stability of single phase solid solution in High Entropy Alloy. The present review examines some of the recent developments while using computational intelligence techniques such as parametric approach, CALPHAD, Machine Learning etc. for prediction of various phase formation in multicomponent high entropy alloys. A detail study of this data-driven approaches pertaining to the understanding of structural and phase formation behaviour of a new class of compositionally complex alloys is done in the present investigation. The advantages and drawbacks of the various computational are also discussed. Finally, this review aims at understanding several computational modeling tools complying the thermodynamic criteria for phase formation of novel HEAs which could possibly deliver superior mechanical properties keeping an aim at advanced engineering applications.

scholarly journals Al, Cu and Zr Addition to High Entropy Alloys: The Effect on Recrystallization Temperature

2018 ◽  
Vol 941 ◽  
pp. 1137-1142
Author(s):  
Elena Colombini ◽  
Andrea Garzoni ◽  
Roberto Giovanardi ◽  
Paolo Veronesi ◽  
Angelo Casagrande
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
Single Phase ◽  
Boundary Energy ◽  
Cold Deformation ◽  
Recrystallization Temperature ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Ni Alloy ◽  
Sluggish Diffusion

The equimolar Cr, Mn, Fe, Co and Ni alloy, first produced in 2004, was unexpectedly found to be single-phase. Consequently, a new concept of materials was developed: high entropy alloys (HEA) forming a single solid-solution with a near equiatomic composition of the constituting elements. In this study, an equimolar CoCrFeMnNi HEA was modified by the addition of 5 at% of either Al, Cu or Zr. The cold-rolled alloys were annealed for 30 minutes at high temperature to investigate the recrystallization kinetics. The evolution of the grain boundary and the grain size were investigated, from the as-cast to the recrystallized state. Results show that the recrystallized single phase FCC structures exhibits different twin grains density, grain size and recrystallization temperatures as a function of the at.% of modifier alloying elements added. In comparison to the equimolar CoCrFeMnNi, the addition of modifier elements increases significantly the recrystallization temperature after cold deformation. The sluggish diffusion (typical of HEA alloys), the presence of a solute in solid solution as well as the low twin boundary energy are responsible for the lower driving force for recrystallization.

Solid State Amorphization and Alloy Parameters for High Entropy Alloys

2021 ◽  
Vol 1016 ◽  
pp. 990-996
Author(s):  
Takeshi Nagase
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Intermetallic Compounds ◽  
Electron Irradiation ◽  
Fast Electron ◽  
High Entropy Alloy ◽  
Solid Solution Formation ◽  
High Entropy ◽  
Solution Formation ◽  
State Amorphization

Fast electron irradiation can induce the solid-state amorphization (SSA) of many intermetallic compounds. The occurrence of SSA stimulated by fast electron irradiation was found in the Al0.5TiZrPdCuNi high-entropy alloy (HEA). The relationship between the occurrence of SSA in intermetallic compounds under fast electron irradiation and the empirical alloy parameters for predicting the solid-solution-formation tendency in HEAs was discussed. The occurrence of SSA in intermetallic compounds was hardly predicted, only by the alloy parameters of δ or ΔHmix, which have been widely used for predicting solid-solution formation in HEAs. All intermetallic compounds with ΔHmix ≤ -35 kJ/mol and those with δ ≥ 12.5 exhibit the occurrence of SSA. This implies that the intermetallic compounds with a largely negative ΔHmix value and a largely positive δ parameter are favorable for the occurrence of SSA.

scholarly journals Prediction of Strength and Ductility in Partially Recrystallized CoCrFeNiTi0.2 High-Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 389 ◽  
Author(s):  
Hanwen Zhang ◽  
Peizhi Liu ◽  
Jinxiong Hou ◽  
Junwei Qiao ◽  
Yucheng Wu
Keyword(s):  
Tensile Strength ◽  
Single Phase ◽  
Volume Fraction ◽  
Tensile Elongation ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Number Density ◽  
High Entropy ◽  
Average Size ◽  
Strength And Ductility

The mechanical behavior of a partially recrystallized fcc-CoCrFeNiTi0.2 high entropy alloys (HEA) is investigated. Temporal evolutions of the morphology, size, and volume fraction of the nanoscaled L12-(Ni,Co)3Ti precipitates at 800 °C with various aging time were quantitatively evaluated. The ultimate tensile strength can be greatly improved to ~1200 MPa, accompanied with a tensile elongation of ~20% after precipitation. The temporal exponents for the average size and number density of precipitates reasonably conform the predictions by the PV model. A composite model was proposed to describe the plastic strain of the current HEA. As a consequence, the tensile strength and tensile elongation are well predicted, which is in accord with the experimental results. The present experiment provides a theoretical reference for the strengthening of partially recrystallized single-phase HEAs in the future.

Cooling Rate and Size Effect on the Microstructure and Mechanical Properties of AlCoCrFeNi High Entropy Alloy

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
F. J. Wang ◽  
Y. Zhang ◽  
G. L. Chen ◽  
H. A. Davies
Keyword(s):  
Solid Solution ◽  
Atomic Ratio ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Body Centered Cubic ◽  
Mechanical Behaviors ◽  
High Entropy ◽  
Intermediate Phases ◽  
Different Diameters ◽  
Very High

High entropy alloys are usually defined as the kind of alloys with at least five principle components, each component has the equi-atomic ratio or near equi-atomic ratio, and the high entropy alloys can have very high entropy of mixing, forming simple solid solution rather than many complex intermediate phases. In this paper, the size effects on the microstructure and mechanical behaviors of a high entropy alloy of AlCoCrFeNi was studied by preparing as-cast rod samples with different diameters. The alloy independent of cast diameter samples has the same phase of body centered cubic solid solution. With decreasing casting diameter, both the strength and the plasticity are increased slightly.

Nanocrystalline single-phase high-entropy alloy synthesized by using intermetallic compound type (TiZrHf)-(NiCuCo) high-entropy metallic glass precursor

2022 ◽  
Vol 209 ◽  
pp. 114391
Author(s):  
Sung Hwan Hong ◽  
Hae Jin Park ◽  
Gyeol Chan Kang ◽  
Young Seok Kim ◽  
Gian Song ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Metallic Glass ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Compound Type

Microstructure Evolution and Hardness of AlCrFeNixMo0.2 High Entropy Alloy

2016 ◽  
Vol 849 ◽  
pp. 40-44 ◽  
Author(s):  
Yong Dong ◽  
Dong Xu Qiao ◽  
Huan Zhi Zhang ◽  
Yi Ping Lu ◽  
Tong Min Wang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Phase Composition ◽  
Intermetallic Compound ◽  
Microstructure Evolution ◽  
Molar Ratio ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Influence Mechanism ◽  
Ni Content ◽  
Compound Matrix

The microstructures, phase composition and hardness of the AlCrFeNixMo0.2 high entropy alloy (x=0.5, 0.8, 1.2 and 1.5, the x values refer to molar ratio) were reported. When the value of x was smaller than 1.2, the alloys consisted of BCC and B2 structures. The BCC and B2 phases were identified to be (Cr, αFe) solid solution and NiAl intermetallic compound, respectively. With the increase of x from 0.5 to 1.2, the microstructure transformed from dendrite/inter-dendrite to eutectic microstructures. When the x was equal to 1.5, besides BCC and B2 phases, another CrFe2.32MoNi phases formed and Net-like (Cr, αFe) phases distributed in the NiAl intermetallic compound matrix. The hardness first decreased then increased with the increase of Ni content. Generally, Ni element is a FCC stabilizer. However, in AlCrFeNixMo0.2 alloys, Ni element promoted the formation of B2 and CrFe2.32MoNi phases. The influence mechanism of Ni element was discussed systematically.

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