Studies on Kinetics of BCC to FCC Phase Transformation in AlCoCrFeNi Equiatomic High Entropy Alloy

2021 ◽  
Vol 52 (5) ◽  
pp. 1679-1688
Author(s):  
J. P. Panda ◽  
P. Arya ◽  
K. Guruvidyathri ◽  
Ravikirana ◽  
B. S. Murty
Keyword(s):  
Phase Transformation ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Fcc Phase ◽  
Kinetics Of

scholarly journals Phase Transformation Kinetics of a FCC Al0.25CoCrFeNi High-Entropy Alloy during Isochronal Heating

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1015
Author(s):  
Jun Wang ◽  
Chen Wei ◽  
Haoxue Yang ◽  
Tong Guo ◽  
Tingting Xu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Activation Energy ◽  
Phase Transformation ◽  
High Entropy Alloy ◽  
Transformation Kinetics ◽  
High Entropy ◽  
Phase Transformation Kinetics ◽  
Diffusion Controlled ◽  
Thermal Dilation ◽  
Kinetics Of

The phase transformation kinetics of a face-centered-cubic (FCC) Al0.25CoCrFeNi high-entropy alloy during isochronal heating is investigated by thermal dilation experiment. The phase transformed volume fraction is determined from the thermal expansion curve, and results show that the phase transition is controlled by diffusion controlled nucleation-growth mechanism. The kinetic parameters, activation energy and kinetic exponent are determined based on Kissinger–Akahira–Sunose (KAS) and Johnson–Mehl–Avrami (JMA) method, respectively. The activation energy and kinetic exponent determined are almost constant, indicating a stable and slow speed of phase transition in the FCC Al0.25CoCrFeNi high-entropy alloy. During the main transformation process, the kinetic exponent shows that the phase transition is diffusion controlled process without nucleation during the transformation.

scholarly journals Orientation Relationships in Al0.7CoCrFeNi High-Entropy Alloy

2017 ◽  
Vol 23 (5) ◽  
pp. 905-915 ◽  
Author(s):  
Leo T.H. de Jeer ◽  
Václav Ocelík ◽  
Jeff T.M. De Hosson
Keyword(s):  
Phase Transformation ◽  
Electron Backscatter Diffraction ◽  
Orientation Distribution ◽  
High Entropy Alloy ◽  
Orientation Relationships ◽  
High Entropy ◽  
Microstructural Evaluation ◽  
Fcc Phase ◽  
Oriented Parallel ◽  
Backscatter Diffraction

AbstractA detailed microstructural evaluation was executed on the crystallographic texture as well as the mechanisms for nucleation, phase transformation, and grain growth in a Al0.7CoCrFeNi high-entropy alloy. The microstructure and crystallographic orientations were characterized by electron backscatter diffraction, and the chemical composition variations by energy-dispersive X-ray spectroscopy. The cast Al0.7CoCrFeNi alloy started in the BCC phase and partially transformed into the FCC phase. It was found that the Pitsch orientation relationship (OR) dominates the nucleation mechanism of the FCC phase; however, deviations with respect to the Pitsch OR are observed and are attributed to the differently sized atoms forming an ordered B2 phase in the alloy causing lattice distortions. The dual phase BCC–FCC microstructure contains FCC Widmanstätten plates oriented parallel to the {110}BCC planes of the parent grain. It was found that the crystal orientation distribution after the BCC–FCC phase transformation is confined and is explained as a product of the governing mechanisms.

scholarly journals Effect of Cold Rolling on the Phase Transformation Kinetics of an Al0.5CoCrFeNi High-Entropy Alloy

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 917 ◽  
Author(s):  
Jun Wang ◽  
Haoxue Yang ◽  
Tong Guo ◽  
Jiaxiang Wang ◽  
William Yi Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Expansion ◽  
Phase Transformation ◽  
Cold Rolling ◽  
High Entropy Alloy ◽  
Transformation Rate ◽  
Transformation Kinetics ◽  
High Entropy ◽  
Phase Transformation Kinetics ◽  
Kinetics Of

The solid state phase transformation kinetics of as-cast and cold rolling deformed Al0.5CoCrFeNi high-entropy alloys have been investigated by the thermal expansion method. The phase transformed volume fractions are determined from the thermal expansion curve using the lever rule method, and the deformed sample exhibits a much higher transformation rate. Two kinetic parameters, activation energy (E) and kinetic exponent (n) are determined using Kissinger– Akahira–Sunose (KAS) and Johnson–Mehl–Avrami (JMA) method, respectively. Results show that a pre-deformed sample shows a much lower activation energy and higher kinetic exponent compared with the as-cast sample, which are interpreted based on the deformation induced defects that can promote the nucleation and growth process during phase transformation.

Phase Transition of As-Milled and Annealed CrCuFeMnNi High-Entropy Alloy Powder

NANO ◽  
2018 ◽  
Vol 13 (09) ◽  
pp. 1850100 ◽  
Author(s):  
Rui-Feng Zhao ◽  
Bo Ren ◽  
Guo-Peng Zhang ◽  
Zhong-Xia Liu ◽  
Jian-Jian Zhang
Keyword(s):  
Phase Transition ◽  
Solution Structure ◽  
Milling Time ◽  
Structure Evolution ◽  
High Entropy Alloy ◽  
Chemical Homogeneity ◽  
High Entropy ◽  
Dynamic Phase Transition ◽  
Fcc Phase ◽  
Bcc Phase

The CrCuFeMnNi high entropy alloy (HEA) powder was synthesized by mechanical alloying. The effects of milling time and subsequent annealing on the structure evolution, thermostability and magnetic property were investigated. After 50[Formula: see text]h of milling, the CrCuFeMnNi HEA powder consisted of a major FCC phase and a small amount of BCC phase. The crystallite size and strain lattice of 50[Formula: see text]h-ball-milled CrCuFeMnNi HEA powder were 12[Formula: see text]nm and 1.02%, respectively. The powder exhibited refined morphology and excellent chemical homogeneity. The supersaturated solid solution structure of the as-milled HEA powder transformed into FCC1, FCC2, a small amount of BCC and [Formula: see text] phase in annealed state. Most of the BCC phase decomposed into FCC (mainly FCC2 phase) and [Formula: see text] phases, and the dynamic phase transition was almost in equilibrium at 900[Formula: see text]C. The saturated magnetization and coercivity force of the 50[Formula: see text]h-ball-milled CrCuFeMnNi HEA powder were respectively 16.1[Formula: see text]emu/g and 56.2[Formula: see text]Oe.

scholarly journals Liquid Supercoolability and Synthesis Kinetics of Quinary Refractory High-entropy Alloy

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
W. L. Wang ◽  
L. Hu ◽  
S. J. Yang ◽  
A. Wang ◽  
L. Wang ◽  
...  
Keyword(s):  
High Entropy Alloy ◽  
High Entropy ◽  
Kinetics Of

scholarly journals On the high temperature coarsening kinetics of γ′ precipitates in a high strength Co37.6Ni35.4Al9.9Mo4.9Cr5.9Ta2.8Ti3.5 fcc-based high entropy alloy

2019 ◽  
Vol 177 ◽  
pp. 82-95 ◽  
Author(s):  
Prafull Pandey ◽  
Sanjay Kashyap ◽  
Dhanalakshmi Palanisamy ◽  
Amit Sharma ◽  
Kamanio Chattopadhyay
Keyword(s):  
High Temperature ◽  
High Strength ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Coarsening Kinetics ◽  
Kinetics Of

Surface hardening of FCC phase high-entropy alloy system by powder-pack boriding

2019 ◽  
Vol 371 ◽  
pp. 389-394 ◽  
Author(s):  
Thomas Lindner ◽  
Martin Löbel ◽  
Benjamin Sattler ◽  
Thomas Lampke
Keyword(s):  
Surface Hardening ◽  
Alloy System ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Fcc Phase

scholarly journals Effect of Mn Addition on the Microstructures and Mechanical Properties of CoCrFeNiPd High Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 288
Author(s):  
Yiming Tan ◽  
Jinshan Li ◽  
Jun Wang ◽  
Hongchao Kou
Keyword(s):  
Intermetallic Compound ◽  
Interface Energy ◽  
High Entropy Alloy ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
Liquid Interfaces ◽  
High Entropy ◽  
Single Face ◽  
Face Centered ◽  
Fcc Phase

CoCrFeNiPdMnx (x = 0, 0.2, 0.4, 0.6, 0.8) high entropy alloys (HEAs) were prepared and characterized. With an increase in Mn addition, the microstructures changed from dendrites (CoCrFeNiPd with a single face-centered-cubic (FCC) phase) to divorced eutectics (CoCrFeNiPdMn0.2 and CoCrFeNiPdMn0.4), to hypoeutectic microstructures (CoCrFeNiPdMn0.6), and finally to seaweed eutectic dendrites (CoCrFeNiPdMn0.8). The addition of Mn might change the interface energy anisotropy of both the FCC/liquid and MnPd-rich intermetallic compound/liquid interfaces, thus forming the seaweed eutectic dendrites. The hardness of the FCC phase was found to be highly related to the solute strengthening effect, the formation of nanotwins and the transition from CoCrFeNiPd-rich to CoCrFeNi-rich FCC phase. Hierarchical nanotwins were found in the MnPd-rich intermetallic compound and a decrease in either the spacing of primary twins or secondary twins led to an increase in hardness. The designing rules of EHEAs were discussed and the pseudo binary method was revised accordingly.

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