Dendritic Growth of Rapid-Solidified Eutectic High-Entropy Alloy

2021 ◽  
Vol 1035 ◽  
pp. 46-50
Author(s):  
Lei Gang Cao ◽  
Peng Yu Hou ◽  
Ahmed Nassar ◽  
Andrew M. Mullis
Keyword(s):  
Cooling Rate ◽  
Single Phase ◽  
Eutectic Growth ◽  
Sample Surface ◽  
Eutectic Structure ◽  
High Entropy Alloy ◽  
Drop Tube ◽  
Dendrite Morphology ◽  
High Entropy ◽  
Mould Casting

Mould casting and drop-tube techniques were used to solidify a AlCoCrFeNi2.1 eutectic high-entropy alloy under conditions of high cooling rate. The samples obtained from two different methods present the same phase constituent, FCC and B2 phases. During mould casting experiments the alloy almost solidified into the eutectic structure consisting of lamellar and anomalous morphology, with a tiny fraction of cellular and dendrite morphology being observed at certain sites of the sample surface due to the corresponding high cooling rate. Instead, during drop-tube experiments a typical, coarse dendrite structure of FCC single phase was formed across the entire 106-150 μm particle. The cellular structure can also be formed directly from the melt. The rest region solidified into the general eutectic morphology as was observed in the casting rods. The results clearly indicate the transition from coupled eutectic growth to single-phase dendrite growth with increasing departures from equilibrium for the multi-component AlCoCrFeNi2.1 eutectic high-entropy alloy.

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.

Design and deformation characteristics of single-phase Co-Cr-Fe-Ni-V high entropy alloy

2021 ◽  
pp. 161579
Author(s):  
Reliance Jain ◽  
M.R. Rahul ◽  
Poulami Chakraborty ◽  
Rama Krushna Sabat ◽  
Sumanta Samal ◽  
...  
Keyword(s):  
Single Phase ◽  
High Entropy Alloy ◽  
Deformation Characteristics ◽  
High Entropy

scholarly journals Phase stability of single phase Al0.12CrNiFeCo high entropy alloy upon irradiation

2018 ◽  
Vol 160 ◽  
pp. 1208-1216 ◽  
Author(s):  
B. Kombaiah ◽  
K. Jin ◽  
H. Bei ◽  
P.D. Edmondson ◽  
Y. Zhang
Keyword(s):  
Phase Stability ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy

Phase stability of a ductile single-phase BCC Hf0.5Nb0.5Ta0.5Ti1.5Zr refractory high-entropy alloy

2018 ◽  
Vol 98 ◽  
pp. 79-88 ◽  
Author(s):  
J.Q. Yao ◽  
X.W. Liu ◽  
N. Gao ◽  
Q.H. Jiang ◽  
N. Li ◽  
...  
Keyword(s):  
Phase Stability ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy

Development of Single-Phase Bcc UHfNbTi High-Entropy Alloy with Excellent Mechanical Properties

2021 ◽  
Author(s):  
J. Shi ◽  
Y.W. Zhao ◽  
Chunli Jiang ◽  
Y.Z. Zhang ◽  
Dongli Zou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy

scholarly journals Thermoelectric Properties of CoCrFeNiNbx Eutectic High Entropy Alloys

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 762
Author(s):  
Kaiming Han ◽  
Hui Jiang ◽  
Tiandang Huang ◽  
Mingyu Wei
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Thermoelectric Properties ◽  
Phase Interface ◽  
Lamellar Microstructure ◽  
Eutectic Structure ◽  
Great Promise ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Nb Content

Bulk CoCrFeNiNb0.45 eutectic high entropy alloy (EHEA) with ultrafine-lamellar microstructure shows outstanding thermal stability. The EHEA offers opportunities for the development of thermoelectric materials. In this paper, the thermoelectric properties of a CoCrFeNiNbx (x = 0, 0.25, and 0.45) EHEA system were investigated. The results indicated that the electrical conductivity decreased with a rise in Nb content in the CoCrFeNiNbx alloys, which resulted from the increased eutectic structure and phase interface. Moreover, the thermal conductivity increased with increased Nb content at low temperature (T ≤ 473 K), while thermal conductivity decreased at high temperature (T > 573 K). The CoCrFeNiNb0.45 full eutectic high entropy alloy exhibited the lowest thermal conductivity and higher thermoelectric figure of merit (ZT) at a high temperature (T > 573 K), which shows great promise for the thermoelectric application at high temperature.

scholarly journals A single-phase bcc high-entropy alloy in the refractory Zr-Nb-Ti-V-Hf system

2018 ◽  
Vol 152 ◽  
pp. 40-43 ◽  
Author(s):  
M. Feuerbacher ◽  
T. Lienig ◽  
C. Thomas
Keyword(s):  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy

scholarly journals Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1020 ◽  
Author(s):  
Bhupendra Sharma ◽  
Kentaro Nagano ◽  
Kuldeep Kumar Saxena ◽  
Hiroshi Fujiwara ◽  
Kei Ameyama
Keyword(s):  
Titanium Hydride ◽  
Single Phase ◽  
Strengthening Mechanism ◽  
High Entropy Alloy ◽  
Mechanically Alloyed ◽  
High Entropy ◽  
Plasma Sintering ◽  
Bcc Structure ◽  
Spark Plasma ◽  
Tih2 Powder

For the first time, an equiatomic refractory high entropy alloy (RHEA) TiNbZrHfTa compact with a single-phase body-centered cubic (BCC) structure was fabricated via a titanium hydride (TiH2) assisted powder metallurgy approach. The constituent pure Ti, Zr, Nb, Hf, and Ta powders were mechanically alloyed (MA) with titanium hydride (TiH2) powder. The resultant MA powder was dehydrogenated at 1073 K for 3.6 ks and subsequently sintered through spark plasma sintering (SPS). Additionally, TiNbZrHfTa counterparts were prepared from pure elements without MA with TiH2. It was observed that the compact prepared from pure powders had a chemically heterogeneous microstructure with hexagonal close packed (HCP) and dual BCC phases. On the other hand, despite containing many constituents, the compact fabricated at 1473 K for 3.6 ks via the hydride approach had a single-phase BCC structure. The Vickers microhardness of the TiNbZrHfTa alloy prepared via the hydride process was Hv 520 (±30). The exceptional microhardness of the alloy is greater than any individual constituent, suggesting the operation of a simple solid-solution-like strengthening mechanism and/or precipitation hardening. In addition, the heat treatments were also carried out to analyze the phase stability of TiNbZrHfTa prepared via the hydride process. The results highlight the substantial changes in the phase as a function of temperature and/or time.

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