scholarly journals Microstructural Stability of the CoCrFe2Ni2 High Entropy Alloys with Additions of Cu and Mo

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1994
Author(s):  
Isaac Toda-Caraballo ◽  
Jose Antonio Jiménez ◽  
Srdjan Milenkovic ◽  
Jorge Jimenez-Aguirre ◽  
David San-Martín
Keyword(s):  
Enthalpy Of Mixing ◽  
High Entropy Alloys ◽  
Surprising Result ◽  
Microstructural Stability ◽  
Rich Phase ◽  
High Entropy ◽  
Single Face ◽  
Precipitation Phenomena ◽  
The Stability ◽  
Fcc Structure

New High Entropy Alloys based on the CoCrFe2Ni2 system have been developed by adding up to 10 at. % of Cu, Mo, and Cu + Mo in different amounts. These alloys showed a single face-centred cubic (FCC) structure after homogenization at 1200 °C. In order to evaluate their thermal stability, aging heat treatments at 500, 700, and 900 °C for 8 h were applied to study the possible precipitation phenomena. In the alloys where only Cu or Mo was added, we found the precipitation of an FCC Cu-rich phase or the µ phase rich in Mo, respectively, in agreement with some of the results previously shown in the literature. Nevertheless, we have observed that when both elements are present, Cu precipitation does not occur, and the formation of the Mo-rich phase is inhibited (or delayed). This is a surprising result as Cu and Mo have a positive enthalpy of mixing, being immiscible in a binary system, while added together they improve the stability of this system and maintain a single FCC crystal structure from medium to high temperatures

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.

Effects of electro-negativity on the stability of topologically close-packed phase in high entropy alloys

2014 ◽  
Vol 52 ◽  
pp. 105-109 ◽  
Author(s):  
Yong Dong ◽  
Yiping Lu ◽  
Li Jiang ◽  
Tongmin Wang ◽  
Tingju Li
Keyword(s):  
High Entropy Alloys ◽  
High Entropy ◽  
Topologically Close Packed ◽  
The Stability ◽  
Electro Negativity

scholarly journals The effect of cooling rate on the magnetic properties of Cu-Fe-Ni multicomponent alloys with Al and Si additions

2018 ◽  
Vol 26 (1) ◽  
pp. 39-44
Author(s):  
O. I. Kushnerov ◽  
V. F. Bashev
Keyword(s):  
Magnetic Properties ◽  
Cooling Rate ◽  
Alloy System ◽  
Enthalpy Of Mixing ◽  
Soft Magnetic Materials ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Leading Role ◽  
The Difference ◽  
Fcc Phase

The paper explores the structure and magnetic properties of multicomponent high-entropy Al-Cu-Fe-Ni-Si alloys in as-cast and splat-quenched state. This alloy system is characterized by the absence of expensive components, such as Co, V, Mo, Cr, usually used for the production of high-entropy alloys while its characteristics are not inferior to those of more expensive alloys. Components of the studied high-entropy alloys were selected taking into account both criteria for designing and estimating their phase composition, which are available in the literature and based on the calculations of the entropy and enthalpy of mixing, and the difference between atomic radii of components as well. The alloy films were fabricated by a known technique of splat-quenching. A cooling rate estimated by film thickness was ~ 106 K/s. Experimental results reveal that the studied alloys except the Al0.5CuFeNi one are multiphase, with the structure consisting of disordered BCC and FCC solid solutions. The Al0.5CuFeNi alloy has only FCC phase. The leading role in determining the type of solid solution formed in the studied high-entropy films obviously plays an element with the highest melting point. All of the investigated multicomponent films are soft magnetic materials as indicated by low values of coercivity, while most of the as-cast alloys are hard-magnetic.

scholarly journals Atomic Displacement and Strength Properties in Equiatomic High Entropy Alloys with the FCC Structure

Materia Japan ◽  
2018 ◽  
Vol 57 (7) ◽  
pp. 312-316
Author(s):  
Norihiko L. Okamoto ◽  
Koretaka Yuge ◽  
Haruyuki Inui
Keyword(s):  
Atomic Displacement ◽  
Strength Properties ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Fcc Structure

Design and High-Throughput Screening of High Entropy Alloys

2021 ◽  
Author(s):  
Yaqi Wu ◽  
Yong Zhang
Keyword(s):  
Solid Solution ◽  
High Throughput ◽  
High Throughput Screening ◽  
Enthalpy Of Mixing ◽  
The Self ◽  
High Entropy Alloys ◽  
Compositional Gradient ◽  
Multiple Targets ◽  
High Entropy ◽  
Ordered Phases

A balanced parameter was proposed to design the high entropy alloys (HEAs), which defined by average melting temperature Tm times entropy of mixing ΔSm over enthalpy of mixing ΔHm, Ω=TmΔSm/ΔHm, if Ω is larger than 1.1, we can predict that the entropy is high enough to overcome the enthalpy, and solid solution is likely to form rather than the intermetallic ordered phases. The composition can be further refined by using high-throughput screening by preparing the compositional gradient films. Multiple targets co-sputtering is usually used to prepare the films, and physical masking can separate the samples independently, chemical masking can also applied if possible. One example is the self-sharpening screening by using nanoindentations, the serration behaviors may related to the self-sharpening compositions.

Microstructure and Properties of Alloys with Equal Atomic Principal Components

2013 ◽  
Vol 765-767 ◽  
pp. 3143-3146
Author(s):  
Yan Ping Wang ◽  
Yu Zhuang ◽  
Jian Chen Li
Keyword(s):  
Solid Solution ◽  
Principal Components ◽  
Argon Atmosphere ◽  
Second Phase ◽  
High Entropy Alloys ◽  
Arc Furnace ◽  
Phase Precipitation ◽  
High Entropy ◽  
Bcc Structure ◽  
Fcc Structure

Four high-entropy alloys are prepared by an arc furnace under argon atmosphere. The microstructure and the properties of the alloys are investigated. The results show that NiCrCuCoFe alloy consists of a single FCC solid solution. When Al presents in the alloys, the microstructures of the alloys change to a BCC+ FCC solid solution. It is indicated that Al element promotes the formation of BCC solid solution, and Si and Mn promote the formation of complicated compounds. The hardness of alloys with BCC structure is higher than that of the alloys with FCC structure. The complicated compounds are formed, the hardness increases further. The highest hardness of the alloys reaches 882 HV due to the strengthening of the second phase precipitation.

Microstructural Evolution and Mechanical Properties in a Mn1.05Fe1.05CoNiCu0.9 High Entropy Alloy

2017 ◽  
Vol 737 ◽  
pp. 44-49 ◽  
Author(s):  
Seung Min Oh ◽  
Sun Ig Hong
Keyword(s):  
Mechanical Properties ◽  
Single Phase ◽  
Cast Alloy ◽  
High Entropy Alloy ◽  
Microstructural Stability ◽  
Dendrite Structure ◽  
High Entropy ◽  
Melting Temperatures ◽  
The Matrix ◽  
Fcc Structure

In the present study, the microstructural stability and mechanical properties of a MnFeCoNiCu alloy in which Cr was replaced by Cu from Cantor composition (CoCrFeMnNi) was studied. In the as-cast alloy, the dendrite arms are enriched with Cu and Mn and matrix between dendrite arms is enriched with Fe and Co. Ni was richer in the matrix, but also observed in the dendrite arms. Cu and Mn tend to segregate and solidify initially because the melting temperatures of Cu and Mn are lower than Fe and Co, resulting in the growth of Cu-Mn dendrite. After homogenization, the dendrites structure disappeared and grain boundaries are visible, indicating the segregated elements in the dendrite structure were homogenized. The presence of single phase FCC structure was confirmed after homogenization. The tensile strength of 1220 MPa with the ductility of 6 % was obtained in MnFeCoNiCu alloy.

Precipitation and its strengthening of Cu-rich phase in CrMnFeCoNiCux high-entropy alloys

2018 ◽  
Vol 713 ◽  
pp. 134-140 ◽  
Author(s):  
Xin Xian ◽  
Lijing Lin ◽  
Zhihong Zhong ◽  
Chao Zhang ◽  
Chang Chen ◽  
...  
Keyword(s):  
High Entropy Alloys ◽  
Rich Phase ◽  
High Entropy
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