scholarly journals An Effective Approach to Acquire the Impurity Diffusion Coefficients in Binary Alloys with Quantified Uncertainties

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 809
Author(s):  
Yueheng Zhang ◽  
Jianpeng Zou ◽  
Xiaoke Wu ◽  
Chunming Deng ◽  
Lijun Zhang
Keyword(s):  
Diffusion Coefficients ◽  
Noble Metals ◽  
Binary Systems ◽  
Binary Alloys ◽  
Radioactive Tracer ◽  
Distribution Functions ◽  
Impurity Diffusion ◽  
Stable Region ◽  
Practical Applications ◽  
Interdiffusion Coefficients

In this paper, we started from the composition-dependent interdiffusion coefficients with quantified uncertainties in binary alloys by integrating the Matano-based method, distribution functions, and uncertainty propagation approach. After carefully defining the numerically stable region for the interdiffusion coefficients, the suitable pre-set functions were screened to achieve the reasonable fit to the D-c and μ-c data according to the Akaike information criterion. With the fitted D-c and μ-c curves, the impurity diffusion coefficients with uncertainties can be directly determined. Benchmark tests in five hypothetical binary systems with different preset D-c relations were then utilized to validate the presently effective approach, followed by practical applications in five real cases, i.e., fcc Ni-Co, fcc Cu-Al, fcc Pt-Ni, hcp Mg-Zn, and bcc Ti-V alloys. The impurity diffusion coefficients with uncertainties derived by the presently effective approach were found to be in excellent agreement with the data by tracer experiments, indicating that this effective approach can serve as a standard one for acquiring the high-quality impurity diffusion coefficients in binary alloys with quantified uncertainties, especially for the noble metals and the cases without suitable radioactive tracer isotopes.

Diffusion of Ti, V and Nb in Ni3Al at Elevated Temperatures

2010 ◽  
Vol 297-301 ◽  
pp. 384-389 ◽  
Author(s):  
Haruhiko Fukaya ◽  
Md. Moniruzzaman ◽  
Yoshinori Murata ◽  
Masahiko Morinaga ◽  
Toshiyuki Koyama ◽  
...  
Keyword(s):  
Experimental Data ◽  
Diffusion Coefficients ◽  
Binary Systems ◽  
Elevated Temperatures ◽  
Diffusion Mechanism ◽  
Impurity Diffusion ◽  
Diffusion Couples ◽  
Different Temperatures ◽  
Series Of Experiments ◽  
Interdiffusion Coefficients

Interdiffusion coefficients of Al replacing elements in Ni-Al-X (X=Ti, V and Nb) were estimated by a series of experiments using diffusion couples of Al rich pseudo-binary systems at three different temperatures of 1423, 1473 and 1523K. In order to obtain interdiffusion coefficients of the pseudo-binary systems, the experimental data was analyzed by the Sauer and Freise method, and also impurity diffusion coefficients of Ti, V and Nb in Ni3Al were estimated by applying the Darken-Manning equation. The magnitude of interdiffusion coefficient decreased in order of V, Ti and Nb at all three temperatures. Impurity diffusion coefficients were described by the expressions: , , . The activation enthalpies obtained from the experimental data confirmed the retardation of Ti, V and Nb diffusion in Ni3Al by the anti-site diffusion mechanism. These results are consistent with our previous work on diffusion of Re and Ru in Ni3Al .

scholarly journals Role of different factors affecting interdiffusion in Cu(Ga) and Cu(Si) solid solutions

2014 ◽  
Vol 470 (2161) ◽  
pp. 20130464 ◽  
Author(s):  
Sangeeta Santra ◽  
Hongqun Dong ◽  
Tomi Laurila ◽  
Aloke Paul
Keyword(s):  
Solid Solutions ◽  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
Impurity Diffusion ◽  
Factors Affecting ◽  
The Matrix ◽  
Bond Strengths ◽  
Interdiffusion Coefficients ◽  
Formation Energies

A detailed diffusion study was carried out on Cu(Ga) and Cu(Si) solid solutions in order to assess the role of different factors in the behaviour of the diffusing components. The faster diffusing species in the two systems, interdiffusion, intrinsic and impurity diffusion coefficients, are determined to facilitate the discussion. It was found that Cu was more mobile in the Cu–Si system, whereas Ga was the faster diffusing species in the Cu–Ga system. In both systems, the interdiffusion coefficients increased with increasing amount of solute (e.g. Si or Ga) in the matrix (Cu). Impurity diffusion coefficients for Si and Ga in Cu, found out by extrapolating interdiffusion coefficient data to zero composition of the solute, were both higher than the Cu tracer diffusion coefficient. These observed trends in diffusion behaviour could be rationalized by considering: (i) formation energies and concentration of vacancies, (ii) elastic moduli (indicating bond strengths) of the elements and (iii) the interaction parameters and the related thermodynamic factors. In summary, we have shown here that all the factors introduced in this paper should be considered simultaneously to understand interdiffusion in solid solutions. Otherwise, some of the aspects may look unusual or even impossible to explain.

Novel Method of Evaluation of Diffusion Coefficients in Ti-Zr System

2008 ◽  
Vol 279 ◽  
pp. 53-62 ◽  
Author(s):  
K. Bhanumurthy ◽  
A. Laik ◽  
G.B. Kale
Keyword(s):  
Diffusion Couple ◽  
Diffusion Zone ◽  
Diffusion Coefficients ◽  
Extended Period ◽  
Impurity Diffusion ◽  
Diffusion Couples ◽  
Simple Method ◽  
Elegant Method ◽  
Method Of Evaluation ◽  
Interdiffusion Coefficients

The incremental diffusion couples are used for evaluating interdiffusion couples in a narrow composition range and these results are extrapolated to get an estimate of impurity diffusion coefficients. In fact, several incremental couples are needed to get impurity diffusion coefficients at different compositions. This process is generally tedious. The present method describes a relatively simple method for evaluating the diffusion coefficients using “step diffusion couples”. A simple experimental method is described to prepare a step diffusion couple. This method involves preparation of diffusion couples in two stages. In the first stage, diffusion couple is made between the two materials in a conventional way and annealed for extended period of time to have a large diffusion zone typically of the order of 2-3 mm. In the second stage, the starting materials are placed on the diffusion couple in a direction perpendicular to the diffusion zone and annealed at a suitable temperature for diffusion to occur between the diffusion zone and the starting materials. This method is applied to study the interdiffusion behavior in the b phase of the Ti-Zr system. Boltzmann-Matano and Hall’s methods were used to determine the interdiffusion coefficients and their composition dependence. Kirkendall shift is observed towards Ti side and the intrinsic diffusion coefficients of Ti is approximately three times that of Zr. The width of the diffusion zone is strongly dependent on the composition of the step diffusion couple. It is observed that the interdiffusion coefficients evaluated at the terminal compositions matched well those published values in the Ti-Zr system. This experimental technique offers an easy and elegant method to determine the diffusion parameters without the tedious preparation of incremental diffusion couples.

scholarly journals Specific-Ion Effects Directed Noble Metal Aerogels: Versatile Manipulation for Electrocatalysis and Beyond

2019 ◽  
Author(s):  
RAN DU ◽  
YUE HU ◽  
René Hübner ◽  
Jan-Ole Joswig ◽  
Xuelin Fan ◽  
...  
Keyword(s):  
Porous Materials ◽  
Noble Metal ◽  
Noble Metals ◽  
Sol Gel ◽  
Synthetic Methods ◽  
Superior Performance ◽  
Gelation Mechanism ◽  
Practical Applications ◽  
Specific Ion Effects ◽  
Ion Effects

<div>Noble metal foams (NMFs) are a new class of functional porous materials featuring properties of both noble metals and monolithic porous materials, providing impressive prospects in catalysis, bio-sensing, plasmonic technologies, etc...Among reported synthetic methods to date, the sol-gel approach manifests overwhelming advantages for versatile synthesis of controlled nanostructured NMFs under mild condition. However, limited gelation methods and insufficient understanding of the underlying mechanism retards structure/composition manipulation of NMFs, hampering ondemand designing for practical applications. Herein highly tunable NMFs are fabricated at room temperature by activating specific-ion effects and regulating ion-nanoparticle interactions, affording various single/alloy NMFs with adjustable compositions (Au, Ag, Pd, Pt), ligament sizes (3.1~142.0 nm), and special morphologies. Their superior performance in programmable self-propulsion devices and electrocatalytic alcohol oxidation are demonstrated. This study provides not only a conceptually new route to fabricate and manipulate functional NMFs, but also an overall picture in understanding the gelation mechanism. It may pave the way for on-target designing versatile NMFs for various applications.</div>

Tracer Impurity Diffusion in Liquid Metals: Zn and Cd in Gallium

1974 ◽  
Vol 29 (6) ◽  
pp. 957-958
Author(s):  
S. J. Larsson ◽  
P.-E. Eriksson
Keyword(s):  
Temperature Dependence ◽  
Diffusion Coefficients ◽  
Liquid Metals ◽  
Impurity Diffusion ◽  
Linear Plot

The diffusion coefficients of 65Zn and 115Cd in liquid Ga have been measured between 27° and 455 °C. The temperature dependence of D can be represented by a linear plot or by an Arrhenius representation with D0=2.1·10-4 cm2/s, Q=1.60 kcal/mol for Zn, and D0=2.3·10-4 cm2/s, Q=1.77 kcal/mol for Cd. An extrapolation to lower temperatures for Zn in Ga connects to the measurements by Belskii et al. The present results imply that for impurity diffusion in liquid Ga the effects of solute mass are more significant than valence effects.

Study by Numerical Simulation of the Structural and Dynamical Properties of the Fused LiCl-KCl Eutectic

1984 ◽  
Vol 39 (2) ◽  
pp. 162-168 ◽  
Author(s):  
F. Lantelme ◽  
P. Turq
Keyword(s):  
Diffusion Coefficients ◽  
Large Range ◽  
Memory Function ◽  
Distribution Functions ◽  
Coulomb Energy ◽  
Radial Distribution Functions ◽  
Volume Changes ◽  
Lithium Ions ◽  
Ionic Motion ◽  
Binary Collisions

The ionic properties of the eutectic LiCl-KCl melt are examined in a large range of temperature and density. The radial distribution functions are calculated. It is shown that, although the contribution of the Coulomb energy to the thermodynamic properties decreases at high temperatures it remains always predominant and explains the temperature dependence of the specific heat at constant volume. The diffusion coefficients of Li+, K+ and Cl- are determined. The mechanism of the ionic motion is studied through the memory function formalism. Two types of motion are detected, which arise from binary collisions and from dynamical events which involve a large number of ions. Temperature and volume changes show that the lithium ions remain always surrounded by a more structured atmosphere which hinders their motion. This effect becomes more apparent at high temperature and low density.

Diffusion and its Application in NiMnGa Alloys

2018 ◽  
Vol 19 ◽  
pp. 80-95 ◽  
Author(s):  
Le Zhou ◽  
Yong Ho Sohn
Keyword(s):  
Crystal Structure ◽  
Martensitic Transformation ◽  
Phase Diagrams ◽  
Diffusion Coefficients ◽  
Diffusion Couples ◽  
Arrhenius Behavior ◽  
Ferromagnetic Shape Memory Alloys ◽  
Two Phase ◽  
Austenitic Phase ◽  
Practical Applications

Heusler NiMnGa alloys are often categorized as ferromagnetic shape memory alloys or magnetocaloric materials, which are important for both practical applications and fundamental research. The NiMnGa alloys undergo a series of diffusion and diffusionless transformation from high temperature to low temperature. Among these transformation, martensitic transformation from austenitic phase to martensitic phase is critical in determining the properties of the alloys. Although martensitic transformation is considered diffusionless, diffusion also has important applications in the research of NiMnGa alloysDiffusion couples along with equilibrium alloys have been used to determine the ternary phase diagrams in NiMnGa alloys. Phase diagrams are important in selecting NiMnGa alloys, in particular two-phase NiMnGa alloys for practical applications. Furthermore, the diffusion couples effectively assist in the determination of compositions that exhibit martensitic transformation temperature near room temperature. Diffusion coefficients have been assessed for NiMnGa alloys. Tracer diffusivity of Ni, Mn and Ga was reported in a wide temperature range and followed Arrhenius behavior. Two different activation energies were obtained, corresponding to B2 and L21 crystal structure, respectively. Interdiffusion coefficients for NiMnGa alloys with B2 crystal structure are measured, which showed that Ni diffuses the fastest, followed by Mn then Ga. The diffusion coefficients provide useful information for fabricating NiMnGa alloys through diffusional process.A combinatorial approach involving diffusion couples and advance characterization has been developed to investigate the mechanical properties, microstructure and crystallography of NiMnGa alloys rapidly and systematically over a large compositional range. The composition-dependent modulus and hardness for NiMnGa alloys was extracted from the diffusion couples with the help of nanoindentation. Martensitic phases with non-modulated and various modulated crystal structures, and austenitic phase were identified in the interdiffusion zones by transmission electron microscopy. The results demonstrate the capability of using diffusion couples to speed up the discovery of new NiMnGa alloys or other similar alloys showing martensitic transformation.

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