Morphological and Crystallographic Characterizations of the Ca-Mg-Zn Intermetallics Appearing in Ternary Diffusion Couples

2011 ◽  
Vol 409 ◽  
pp. 387-392 ◽  
Author(s):  
Yi Nan Zhang ◽  
Dmytro Kevorkov ◽  
Florent Bridier ◽  
Mamoun Medraj
Keyword(s):  
Diffusion Zone ◽  
Crystal Orientation ◽  
Morphological Evolution ◽  
Morphological Characteristics ◽  
Diffusion Couples ◽  
Ternary Diffusion ◽  
Orientation Relations ◽  
Quantitative Electron Probe Microanalysis ◽  
Multi Phase ◽  
Electron Back Scattered Diffraction

In the present research, seven multi-phase diffusion couples, with terminal alloys having different microstructural features, were prepared and annealed for 4 weeks at 335°C. The phase relations and change of morphological characteristics of each phase were studied along the diffusion zone by means of scanning electron microscopy/energy dispersive X-ray spectroscopy and quantitative electron probe microanalysis. Depending on the different terminal compositions of the diffusion couples, the morphological evolution in the diffusion zone can be: tooth-like, matrix phase with isolated and/or dendritic precipitates. Electron back-scattered diffraction analysis was carried out to investigate the crystal orientation of the ternary compounds and the crystal orientation relations at the interface of the diffusion zones.

On the properties of α/α+β ternary diffusion couples

2000 ◽  
Vol 48 (2) ◽  
pp. 481-492 ◽  
Author(s):  
W.J Boettinger ◽  
S.R Coriell ◽  
C.E Campbell ◽  
G.B McFadden
Keyword(s):  
Diffusion Couples ◽  
Ternary Diffusion

Diffusionsuntersuchungen im System Palladium—Vanadium mit Hilfe der Mikrosonde / Diffusion In The System Pd—V Investigated By Means Of An Electron Microprobe

1972 ◽  
Vol 27 (6) ◽  
pp. 960-965 ◽  
Author(s):  
Peter Lamparter ◽  
Traudl Krabichler ◽  
Siegfried Steeb
Keyword(s):  
Diffusion Zone ◽  
Solid Solubility ◽  
Electron Probe ◽  
Diffusion Processes ◽  
Kirkendall Effect ◽  
Layer Growth ◽  
Arrhenius Law ◽  
Intrinsic Diffusion ◽  
Quantitative Electron Probe Microanalysis

Abstract Diffusion processes (600 to 1300 °C) were investigated by means of quantitative electron-probe-microanalysis. The composition of the diffusion zone corresponds quite well with the phase diagram. The following phases were observed: Pd-solid solubility, Pd3V, Pd2V, and V-solid solubility. Below 900 °C the growth of the diffusion zone is retarded; above 900 °C the layer grows according to d = k ·√t. For all phases observed, according to Matano's method the coefficients of the inter-diffusion were determined. The temperature dependency of these coefficients as well as that of the k-values follows an Arrhenius law. Thus the activation energies of the layer growth and of the interdiffusion were obtained. The determination of the intrinsic diffusion coefficients by the observation of the Kirkendall-effect is discussed.

scholarly journals Morphological Evolutions of Ni-Rich Phases in Al-Si Piston Alloys during 250–400 °C Thermal Exposure Processes

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5212
Author(s):  
Haowei An ◽  
Jiwei Geng ◽  
Zeyu Bian ◽  
Gen Liu ◽  
Mingliang Wang ◽  
...  
Keyword(s):  
Morphological Evolution ◽  
Morphological Characteristics ◽  
Hardness Test ◽  
Thermal Exposure ◽  
Micro Hardness ◽  
Morphological Transformation ◽  
Alloy Hardness ◽  
The Matrix ◽  
Hardness Increase ◽  
Exposure Process

The thermal stability of the Al-Si alloys during the thermal exposure process from 250 °C to 400 °C was systematically investigated. The relationships between the morphological evolution and the mechanical changes of the alloys were determined through the Vickers hardness test and materials characterization method. Initially, the alloys exhibited similar thermal degradation behavior. For example, the exposure process of the alloy at 300 °C can be divided into two stages according to the changes of the alloy hardness and the matrix micro-hardness. In detail, the first stage (0–2 h) exhibited a severe reduction of the alloy hardness while the second stage showed a more leveled hardness during the following 98 h. There are three identified morphological characteristics of Ni-rich phases in the alloy. Furthermore, the differences in both composition and the micro-hardness between these Ni-rich phases were confirmed. The underlying relationships between the morphological transformation of the Ni-rich phases and hardness fluctuation in the alloy were correlated and elucidated. The observed alloy hardness increase when the exposure temperature was 400 °C was unexpected. This behavior was explained from the perspectives of both Ni-rich phases evolution and dispersoid formation.

Application of a Crystal Orientation Method for Matching Surfaces Along a Fracture Line

2008 ◽  
Author(s):  
Barbara K. Lograsso ◽  
Thomas A. Lograsso ◽  
Ryan J. Glamm
Keyword(s):  
Crystal Orientation ◽  
Orientation Imaging Microscopy ◽  
Fracture Plane ◽  
Orientation Imaging ◽  
Metal Fracture ◽  
Single Piece ◽  
Orientation Method ◽  
Electron Back Scattered Diffraction ◽  
Actual Fracture

The overall objective of this study was to evaluate whether surface crystal orientation can be used to associate metal fracture fragments. This study examined the orientations of the fractured crystals across the fracture plane for two surfaces determined to be a matching fracture by conventional methods. This study used Electron Back-Scattered Diffraction (EBSD), sometimes known as Orientation Imaging Microscopy (OIM), to determine the crystallographic orientation of individual metal crystals along the length of the fracture on a surface perpendicular to the actual fracture surface. This investigation examined the uniqueness of crystal orientations within a metal and examined the requirements necessary for determination of crystallography using EBSD. This study also examined the crystallographic information as to whether it is sufficiently reliable characteristic from which a quantitative determination could be made that two separate pieces of metal are, in fact, from a single piece.

The Ni-Al-Zr Multiphase Diffusion Simulations

2015 ◽  
Vol 34 (5) ◽  
Author(s):  
Bartek Wierzba ◽  
Jolanta Romanowska ◽  
Maryana Zagula-Yavorska ◽  
Janusz Markowski ◽  
Jan Sieniawski
Keyword(s):  
Mass Transport ◽  
Diffusion Zone ◽  
Quantitative Description ◽  
Pure Nickel ◽  
Phase Volume ◽  
Volume Fractions ◽  
Aluminide Coatings ◽  
Multiphase Diffusion ◽  
Multi Phase ◽  
Diffusion Mass

AbstractThe generalized Darken method allows a quantitative description of diffusion mass transport in multi-phase materials. The method characterizes the diffusion zone by phase volume fractions. The results of the calculations are compared with experimental concentration’s profiles of nickel, zirconium and aluminum in zirconium doped aluminide coatings deposited on pure nickel by the PVD and CVD methods.

Determination of Average Ternary Interdiffusion Coefficients Using Moments of Interdiffusion Flux and Concentration Profiles

2010 ◽  
Vol 297-301 ◽  
pp. 1328-1333
Author(s):  
N. Garimella ◽  
H.J. Choi ◽  
Yong Ho Sohn
Keyword(s):  
Analysis Method ◽  
Diffusion Couples ◽  
Rigorous Solution ◽  
Ternary Diffusion ◽  
Flux Flow ◽  
Flow Equations ◽  
Interdiffusion Flux ◽  
Validation Criteria ◽  
Interdiffusion Coefficients

We developed a method of rigorous solution of the Onsager’s flow equations using moments of the interdiffusion-parameter integrands for the determination of average ternary interdiffusion coefficients. The analysis developed by Dayananda and Sohn [1] is the basis for this refined approach. Average main and cross interdiffusion coefficients are determined over selected regions in the diffusion zone using the diffusion-distance moments of the interdiffusion flux flow equations. Thermodynamic stability of solid solutions in the light of interdiffusion phenomenon is taken as validation criteria to identify accurate and reliable values of the ternary interdiffusion coefficients. Regulations are proposed for successful application of the analysis method to various ternary diffusion couples in Ni- and Fe-based intermetallics.

scholarly journals Application of numerical inverse method in calculation of composition-dependent interdiffusion coefficients in finite diffusion couples

10.30544/308 ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 197-211 ◽  
Author(s):  
Yuanrong Liu ◽  
Weimin Chen ◽  
Jing Zhong ◽  
Ming Chen ◽  
Lijun Zhang
Keyword(s):  
Diffusion Couple ◽  
Inverse Method ◽  
Diffusion Path ◽  
Diffusion Couples ◽  
Ternary Diffusion ◽  
Inverse Approach ◽  
Ternary Diffusion Couple ◽  
Composition Profiles ◽  
Standard Sets ◽  
Interdiffusion Coefficients

The previously developed numerical inverse method was applied to determine the composition-dependent interdiffusion coefficients in single-phase finite diffusion couples. The numerical inverse method was first validated in a fictitious binary finite diffusion couple by pre-assuming four standard sets of interdiffusion coefficients. After that, the numerical inverse method was then adopted in a ternary Al-Cu-Ni finite diffusion couple. Based on the measured composition profiles, the ternary interdiffusion coefficients along the entire diffusion path of the target ternary diffusion couple were obtained by using the numerical inverse approach. The comprehensive comparisons between the computations and the experiments indicate that the numerical inverse method is also applicable to high-throughput determination of the composition-dependent interdiffusion coefficients in finite diffusion couples.

scholarly journals Rates of morphological evolution in Captorhinidae: An adaptive radiation of Permian herbivores

2017 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Causal Relationship ◽  
Adaptive Radiation ◽  
Morphological Evolution ◽  
Morphological Characteristics ◽  
Terrestrial Ecosystems ◽  
Evolutionary Patterns ◽  
Evolutionary Innovation ◽  
Rates Of Evolution ◽  
Key Innovation ◽  
The Impact

The evolution of herbivory in early tetrapods was crucial in the establishment of terrestrial ecosystems, although it is so far unclear what effect this innovation had on the macro-evolutionary patterns observed within this clade. The clades which entered this under-filled region of ecospace might be expected to have experienced an “adaptive radiation”: an increase in rates of morphological evolution and speciation driven by the evolution of a key innovation. However such inferences are often circumstantial, being based on the coincidence of a rate shift with the origin of an evolutionary novelty. The conclusion of an adaptive radiation may be made more robust by examining the pattern of the evolutionary shift; if the evolutionary innovation coincides not only with a shift in rates of morphological evolution, but specifically in the morphological characteristics relevant to the ecological shift of interest, then one may more plausibly infer a causal relationship between the two. Here I examine the impact of diet evolution on rates of morphological change in one of the earliest tetrapod clades to evolve high-fibre herbivory: Captorhinidae. Using a method of calculating heterogeneity in rates of discrete character change across a phylogeny, it is shown that a significant increase in rates of evolution coincides with the transition to herbivory in captorhinids. Theherbivorous captorhinids also exhibit greater morphological disparity than their faunivorous relatives, indicating more rapid exploration of new regions of morphospace. As well as an increase in rates of evolution, there is a shift in the regions of the skeleton undergoing the most change; the character changes in the herbivorous lineages are concentrated in the manible and dentition. The fact that the increase in rates of evolution coincides with increased change in characters relating to food acquisition provides stronger evidence for a causal relationship between the herbivorous diet and the radiation event.

A Limited Condition for Bifurcate or Trifurcate Kirkendall Planes in Multiple Phase Diffusion Couples

2010 ◽  
Vol 297-301 ◽  
pp. 1487-1492 ◽  
Author(s):  
Toshitada Shimozaki ◽  
Takahisa Okino ◽  
C.G. Lee ◽  
O. Taguchi
Keyword(s):  
Diffusion Couple ◽  
Molar Volume ◽  
Volume Change ◽  
Numerical Technique ◽  
Diffusion Couples ◽  
Phase Diffusion ◽  
Multiple Phase ◽  
Change Effect ◽  
Lattice Planes ◽  
Multi Phase

In general, only one Kirkendall plane can be seen in a diffusion couple. However, bifurcate or trifurcate Kirkendall planes have been reported in Ti/TiAl3 or Co/CoSi2 multi-phase diffusion couples (M-couple) [1,2]. The authors [3] have previously shown a numerical technique to analyze the movement of multiple markers (M-M) embedded in a M-couple taking the molar volume change effect to the diffusion direction into account. Using this technique, one can visualize the places where vacancies (lattice planes) are annihilated or generated in the couple. Here, we try to demonstrate the bifurcate or trifurcate Kirkendall planes in the M-couple and clarify the limited conditions of bifurcate or trifurcate Kirkendall planes by using this numerical technique.

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