scholarly journals Automation of diffusion database development in multicomponent alloys from large number of experimental composition profiles

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jing Zhong ◽  
Li Chen ◽  
Lijun Zhang
Keyword(s):  
High Quality ◽  
High Entropy ◽  
Database Development ◽  
Diffusion Controlled ◽  
Mobility Database ◽  
Temperature Ranges ◽  
Composition Profiles ◽  
Efficient Extraction ◽  
Sluggish Diffusion ◽  
Interdiffusion Coefficients

AbstractNowadays, the urgency for the high-quality interdiffusion coefficients and atomic mobilities with quantified uncertainties in multicomponent/multi-principal element alloys, which are indispensable for comprehensive understanding of the diffusion-controlled processes during their preparation and service periods, is merging as a momentous trending in materials community. However, the traditional exploration approach for database development relies heavily on expertize and labor-intensive computation, and is thus intractable for complex systems. In this paper, we augmented the HitDIC (high-throughput determination of interdiffusion coefficients, https://hitdic.com) software into a computation framework for automatic and efficient extraction of interdiffusion coefficients and development of atomic mobility database directly from large number of experimental composition profiles. Such an efficient framework proceeds in a workflow of automation concerning techniques of data-cleaning, feature engineering, regularization, uncertainty quantification and parallelism, for sake of agilely establishing high-quality kinetic database for target alloy. Demonstration of the developed infrastructures was finally conducted in fcc CoCrFeMnNi high-entropy alloys with a dataset of 170 diffusion couples and 34,000 composition points for verifying their reliability and efficiency. Thorough investigation over the obtained kinetic descriptions indicated that the sluggish diffusion is merely unilateral interpretation over specific composition and temperature ranges affiliated to limited dataset. It is inferred that data-mining over large number of experimental data with the combinatorial infrastructures are superior to reveal extremely complex composition- and temperature-dependent thermal–physical properties.

The Growth Rates of Intermediate Phases in Co/Si Diffusion Couples: Bulk Versus Thin-Film Studies

1989 ◽  
Vol 148 ◽  
Author(s):  
C. H. Jan ◽  
J. C. Lin ◽  
Y. A. Chang
Keyword(s):  
Experimental Data ◽  
Growth Rates ◽  
Film Studies ◽  
Bulk Diffusion ◽  
Diffusion Equations ◽  
Diffusion Couples ◽  
Intermediate Phases ◽  
Diffusion Controlled ◽  
Composition Profiles ◽  
Interdiffusion Coefficients

ABSTRACTBulk diffusion couples of Co/Si were annealed at 800, 900, 1000, 1050 and 1100°C for periods ranging from 24 hours to one month. Growth rates of the intermediate phases, Co2Si, CoSi and CoSi2, as well as the composition profiles across the couples were determined by optical microscopy and electron probe microanalysis (EPMA). Using the solution to the multiphase binary diffusion equations and the experimental data, the interdiffusion coefficients for Co2Si, CoSi and CoSi2 are obtained as a function of temperature. The activation energies obtained are 140, 160 and 190 KJ/mole for Co2Si, CoSi and CoSi2, respectively. The generally small interdiffusion coefficient of CoSi2 and its high activation energy cause the growth rate of CoSi2 to be extremely small at low temperatures.The interdiffusion coefficients for Co2Si, CoSi and CoSi2 at 545°C are obtained by extrapolation of the high-temperatures data. Using these data and solving numerically the diffusion equations with the appropriate boundary conditions, the growth of Co2Si, CoSi and CoSi2 is calculated as a function of time. The calculated results are in good agreement with the experimental data reported in the literature. This study demonstrates clearly that the initial absence of the CoSi2 phase is due to diffusion-controlled rather than nucleation-controlled kinetics. This phenomenon may be quite common in many thin-fiflm metal/Si couples.

Investigation of Interdiffusion in High Entropy Alloys: Application of the Random Alloy Model

2019 ◽  
Vol 22 ◽  
pp. 94-108
Author(s):  
Mohammad Afikuzzaman ◽  
Irina V. Belova ◽  
Graeme E. Murch
Keyword(s):  
Diffusion Couple ◽  
High Entropy Alloys ◽  
Diffusion Couples ◽  
High Entropy ◽  
Significant Difference ◽  
Composition Profiles ◽  
Random Alloy ◽  
Explicit Finite Difference ◽  
Interdiffusion Coefficients ◽  
Good Agreement

High entropy alloys (HEAs) are composed of five or more principal elements with equal (or nearly equal) compositions. In this paper, interdiffusion phenomenon in the HEAs is investigated. Two composition dependent (as well as composition independent) interdiffusion matrices have been used for detailed studying of the diffusion behaviour in CoCrFeMnNi HEAs. These matrices are calculated according to the Darken and Manning formalisms and are used in combination with the explicit finite difference method (EFDM) to obtain interdiffusion profiles. First, the interdiffusion profiles are calculated for the case of the terminal binary diffusion couple. A significant difference in the composition profiles is found between predictions according to the Darken and Manning formalisms. Next, the interdiffusion problem in the 5-component alloy is addressed numerically by considering the interdiffusion coefficients as constant, independent of composition, in CoCrFeMnNi alloys for several diffusion couples (mainly quasi-binary and quasi-ternary). The simulated composition profiles are found to be in a very good agreement with the available experimental results [1, 2]. It should be pointed out that the independence on composition of the interdiffusion matrix should be used for diffusion couples under two conditions: relatively small changes in composition, and the non-zero/non-dilute terminal compositions. The composition dependent interdiffusion matrix should be used in the diffusion couple if the composition differences are large and/or zero/dilute terminal compositions. In this paper, the Darken and Manning formalisms are used for modelling the composition dependent interdiffusion matrices. The purpose of this modelling is to systematically investigate interdiffusion in CoCrFeMnNi alloys in diffusion couples with substantial changes in composition. The main application of the present research is in the prediction of possible interdiffusion profiles in the framework of the random alloy model.

scholarly journals High-Entropy Alloys for Advanced Nuclear Applications

Entropy ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 98
Author(s):  
Ed J. Pickering ◽  
Alexander W. Carruthers ◽  
Paul J. Barron ◽  
Simon C. Middleburgh ◽  
David E.J. Armstrong ◽  
...  
Keyword(s):  
Austenitic Steels ◽  
Irradiation Damage ◽  
High Entropy Alloys ◽  
Damage Resistance ◽  
High Entropy ◽  
Engineering Alloys ◽  
Sluggish Diffusion ◽  
Work Done ◽  
Current Engineering ◽  
Nuclear Applications

The expanded compositional freedom afforded by high-entropy alloys (HEAs) represents a unique opportunity for the design of alloys for advanced nuclear applications, in particular for applications where current engineering alloys fall short. This review assesses the work done to date in the field of HEAs for nuclear applications, provides critical insight into the conclusions drawn, and highlights possibilities and challenges for future study. It is found that our understanding of the irradiation responses of HEAs remains in its infancy, and much work is needed in order for our knowledge of any single HEA system to match our understanding of conventional alloys such as austenitic steels. A number of studies have suggested that HEAs possess `special’ irradiation damage resistance, although some of the proposed mechanisms, such as those based on sluggish diffusion and lattice distortion, remain somewhat unconvincing (certainly in terms of being universally applicable to all HEAs). Nevertheless, there may be some mechanisms and effects that are uniquely different in HEAs when compared to more conventional alloys, such as the effect that their poor thermal conductivities have on the displacement cascade. Furthermore, the opportunity to tune the compositions of HEAs over a large range to optimise particular irradiation responses could be very powerful, even if the design process remains challenging.

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.

High-quality multilayer graphene on an insulator formed by diffusion controlled Ni-induced layer exchange

2017 ◽  
Vol 111 (24) ◽  
pp. 243104 ◽  
Author(s):  
H. Murata ◽  
N. Saitoh ◽  
N. Yoshizawa ◽  
T. Suemasu ◽  
K. Toko
Keyword(s):  
Multilayer Graphene ◽  
High Quality ◽  
Diffusion Controlled

Sluggish diffusion in Co–Cr–Fe–Mn–Ni high-entropy alloys

2013 ◽  
Vol 61 (13) ◽  
pp. 4887-4897 ◽  
Author(s):  
K.-Y. Tsai ◽  
M.-H. Tsai ◽  
J.-W. Yeh
Keyword(s):  
High Entropy Alloys ◽  
High Entropy ◽  
Sluggish Diffusion

A New Diffusivity Database for Multi-Component Al Alloys: Focusing on Ternary Systems and its Effect on Microstructure Evolution during Solidification

2014 ◽  
Vol 794-796 ◽  
pp. 611-616 ◽  
Author(s):  
Li Jun Zhang ◽  
Dan Dan Liu ◽  
Wei Bin Zhang ◽  
Shao Qing Wang ◽  
Ying Tang ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Hybrid Approach ◽  
Ternary Systems ◽  
Atomic Mobility ◽  
First Principles Calculations ◽  
Liquid Phases ◽  
Diffusion Controlled ◽  
Mobility Database ◽  
Diffusion Paths ◽  
Diffusion Properties

A new atomic mobility database for Fcc_A1, L12, Bcc_A2, Bcc_B2, and liquid phases in the Al-Cu-Fe-Mg-Mn-Ni-Si-Zn system has been established via a hybrid approach of experiment, first-principles calculations and DICTRA (DIffusion Controlled TRAnsformation) software, focusing on the atomic mobility parameters in ternary systems. Various diffusivities can be computed as a function of temperature and composition. The reliability of this diffusivity database is further validated by comparing the calculated and measured diffusion properties in a series of ternary and quaternary diffusion couples, including concentration profiles, diffusion paths, interdiffusion fluxes, and so on. The effect of the diffusivity database on microstructure evolution during solidification is demonstrated by the phase field simulation of primary (Al) grains in Al356.1 alloy. The simulation results indicate that such accurate diffusivity database is highly needed for the quantitative simulation of microstructural evolution during solidification.

First report on entire sets of experimentally determined interdiffusion coefficients in quaternary and quinary high-entropy alloys

2020 ◽  
Vol 35 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Vivek Verma ◽  
Aparna Tripathi ◽  
Thiruvenkatam Venkateswaran ◽  
Kaustubh N. Kulkarni
Keyword(s):  
High Entropy Alloys ◽  
First Report ◽  
High Entropy ◽  
Image Position ◽  
Interdiffusion Coefficients

Abstract

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.

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