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This paper addresses a current debate about the morphology of M7C3 phase in the chrome carbide overlay (CCO) and white iron community. This morphology was investigated using a serial sectioning technique in combination with computer post-processing software. A 600×600×300 μm volume of CCO was reconstructed in three dimensions (3D) to determine the difference between blade and rod-like carbide morphologies. The 3D analysis revealed that the two carbides morphologies correspond to the same hexagonal rod-like structures, but are oriented in different directions relative to the sectioning plane.

In this work, the microstructure of an Al 3 Nb–Nb 2 Al–AlNbNi ternary eutectic obtained by directional solidification was analyzed. Because the phase arrangement of this eutectic is highly complex, this study involved a three-dimensional reconstruction of the microstructure using the serial sectioning technique. The visualization of the reconstructed microstructure revealed that the fibers possessed a high degree of sinuosity. Although these fibers were continuous in the growth direction, they displayed a tendency to move back and forth across a central axis.

Reconstruction and visualization of three-dimensional (3-D) pores are of interest for understanding microstructure–properties relationships in cast Mg-alloys. In this contribution, a montage serial sectioning technique is applied to reconstruct a large volume of the 3-D microstructure of a new high-pressure die-cast AE44 Mg-alloy at a high resolution. The 3-D reconstruction reveals that the shapes and morphologies of the gas pores in the AE44 alloy are substantially different from those in other important cast Mg-alloys, which may partly account for the AE44 alloy’s superior properties.

The contour method, a newly-invented sectioning technique for residual stress measurement, has the potential to measure the cross-sectional residual stress profile of a weld in a simple and time-efficient manner. In this paper we demonstrate the capability of the contour method to measure cross-sectional residual stress profiles, which are compared with neutron diffraction measurements and show excellent agreement. The results provide useful information for safetycritical design of welded components and optimization of welding parameters, and also illustrate the potential of the contour technique as a powerful tool for residual stress evaluation.

The variation in the position of antipodal cells before and after fertilization in polyembryonic rice strain Ap III was studied by using conventional sectioning technique. It was shown that initially the three antipodal cells lie at the chalazal end of the young embryo sacs. Along with the development of embryo sac, the antipodal cells proliferate into a multicellular structure containing up to about 20 cells. Most of the cellsmigrate to its dorsal side when the embryo sacs turn into mature. In a few embryo sacs the antipodal cells are situated in the positions adjacent to the egg apparatus at the micropylar end, while in other sacs, they spread from the midst of the embryo sac to the micropylar end clinging to the nucellar tissue. Furthermore, it is reported for the first time that cells of some egg apparatus or proembryos disorganize when antipodal cells lie at the micropylar end, indicating that the function of the antipodal cells may vary during the embryogenesis in rice Ap III.

Damage in materials can be represented in many forms such as specific void or crack surfaces, the spacing between cracks, scalar representation of damage and general tensorial representation of damage. This paper presents methods to quantify the specific damaged surface area, the specific damaged surface area tensor, the damage tensor, the mean solid path among the damaged surfaces and the mean solid path tensor. The methods are general and use the reconstructed three-dimensional structure from tomography images and a virtual sectioning technique to obtain cross-sectional images needed for the quantification. The paper also presents the relation between the quantified damage parameters and their applications in mechanical modeling. This work is applied in particular to quantify the damage parameters of asphalt concrete specimens of the WesTrack project.

Grain boundary and interphase boundary diffusion has been investigated in the system Ag/Ni using the radiotracer serial sectioning technique. Ni segregation in Ag grain boundaries is strongly temperature dependent leading to the conclusion that Ni atoms are located mainly in the bulk planes adjacent to the grain boundary. From interphase boundary diffusion measurements in (110) oriented Ag/Ni interphase boundaries it can be deduced that the structure of this interphase boundary is incoherent.

The diffusion of Fe and Ge in the D03 phase Fe3Si has been studied as a function of temperature and composition using a tracer sectioning technique and the radioisotopes 59Fe and 71Ge. One experiment with the short-lived 31Si radiotracer was carried out to examine the similarity of Ge diffusion and Si diffusion. These elements diffuse with similar rates. The results are discussed considering composition dependences, magnetic and ordering transitions. The most striking fact is that Fe diffusion in the D03 structure Fe3Si is much faster and the corresponding activation enthalpy is considerably lower than in bcc Fe or in disordered Fe-rich Fe-Si alloys. By contrast, diffusion of Ge and Si is a great deal slower and the activation enthalpy is higher than in the disordered phases. While Fe diffusion is strongly dependent on the alloy composition, diffusion of Ge in Fe3Si is less affected by the Si content. Possible diffusion mechanisms are discussed in the light of additional information on Fe3Si. The...

Measurements of Co diffusion in α-Ti were made by using radiotracers and the direct sectioning technique. The Arrhenius plot obtained is a straight line for the whole range of temperature covered (619–823 K) with Q = 127 ± 6 kJ mol−1 and D o = (3 ± 1)× 10−6m2s−1. The results show an excellent agreement with previous ones in the range (871–1135 K) and they suggest that there is no ultrafast impurity influence in the diffusion in the α-Ti matrix.

Results on the diffusion of Cl into CdTe are described. Diffusion anneals were carried out at selected temperatures in the range between 200 degrees C and 700 degrees C in evacuated SiO2 ampoules using a diffusion source of CdCl2 under saturated vapour pressure conditions. The concentration profiles were measured using a radiotracer sectioning technique. The profiles were found to be composed of four parts, to which a computer package consisting of the sum of four complementary error functions (erfc) gave satisfactory fits to the data. The fastest-diffusing component gave values of the diffusivity that agreed with previously published results. Proposals explaining how this type of diffusion may occur are given.

The diffusion behaviour of 95 Zr tracer in a series of ZrAg alloys (0–5.15 at% Ag) is investigated in the temperature range between 1200 and 1520 K, by employing the serial sectioning technique. The self-diffusivity data have been analysed on the basis of the “omega-embryo” mechanism. Based on this data, “omega”-instability temperatures in ZrAg alloys have been evaluated. It is observed that the instability temperature decreases with increase in the sliver concentration in the alloy.

Die Diffusionsparameter von Stickstoff (0 bis etwa 0.3 Ma%) in hochlegierten austenitischen Stahlen (12 bis 19 Ma%Cr, 12 bis 16 Ma%Ni, 0 bis 2 Ma%Mo) wurden im Temperaturbereich von 1283 bis 1573K ermittelt. Die geringen Konzentrationsgradienten von N konnten mittels folgender Methoden erfolgreich untersucht werden: (1) Kombination von mechanischer Schichtenteilung und chemischer N-Analyse bzw. Rontgenstrahl-Gitterparametermessung (2) Elektronenstrahl-Mikroanalyse (ESMA) oder KOSSEL-Ruckstrahltechnik am metallografischen Querschliff. Die N-Diffusionskoeffizienten (DK) wurden als konzentrationsunabhangig gefunden. Die Legierungselemente Cr und Mo senken das Diffusionsvermogen des N in hochlegierten austenitischen Stahlen, welches andererseits durch Ni erhoht wird. Eine Erklarung dafur kann im Zusammenhang mit einer Analyse der Wechselwirkungsparameter gegeben werden. Interdiffusion of nitrogen in high-alloy austenitic CrNi(Mo) steels Parameters of the diffusion of N (0 to 0.3 wt.%) in austenitic stainless steels (12 to 19 wt.%Cr, 12 to 16 wt.%Ni, 0 to 2 wt.%Mo) were determined within the temperature range of 1283–1573K. The small concentration gradients of N were successfully investigated using (1) mechanical serial sectioning technique in combination with either chemical N analysis or x-ray precision lattice parameter determination, (2) measurements on microsections by means of either Electron Probe Microanalysis or KOSSEL technique. The diffusion coefficients of N were found to be independent of its concentration. The alloying elements Cr and Mo reduce the N diffusivity in austenitic stainless steels which on the other hand is increased by Ni. An explanation of these results can be given in connection with the analysis of interaction parameters.

The diffusion of 59Fe in Incoloy 800 has been studied using the serial sectioning technique in the temperature ranges 1020–1500 K for volume diffusion and 750–1100 K for grain boundary diffusion, respectively. The volume diffusion coefficients can be represented by the expression: D(1020–1500 K)=3·26×10−5 exp (−259·6 kJ mol−1/RT) m2 s−l. The grain boundary diffusion coefficients were evaluated in most of the experiments using Whipple's method. For afew specimens, Suzuoka's method was applied. The penetration depths beyond which these methods were to be applied to analyse the experimental results were determined both graphically and by extensive use of autoradiographic techniques. The grain boundary diffusivities can be expressed as: Dgb (750–1100 K)=1·88×10−5 exp (−160·7 kJ mol−1/RT) m2 s−1, The results are discussed and presented in this paper.MST/l193

Grain-boundary heterodiffusion of iron in pure copper and self diffusion of iron in copper–0.091at% iron were measured by the serial sectioning technique in the Harrison B-regime. The penetration profiles corresponding to iron heterodiffusion in pure copper show a strong positive curvature far beyond the (Dvt)1/2 depth . This peculiar shape, which does not exist for self diffusion in the solid solution, proves the presence of a strong non linear grain-boundary segregation of iron in copper in spite of the respective surface energies of these metals. This segregation is linked to the size effect which is, as predicted by numerical simulation, the main driving force for grainboundary segregation.

Objectives . Focused ion-beam (FIB) etching, commonly used as a cross-sectioning technique for failure analysis of semiconductor devices, has recently been applied to biological tissues to expose their ultrastructure for examination. It was the aim of this investigation to determine the practical utility of FIB to cross-section resin-dentin interfaces in order to morphologically evaluate the completeness of resin penetration into the exposed collagen scaffold at the resin-dentin bond interface. Methods . Two representative commercially available dentin adhesive systems were bonded to mid-coronal dentin. After appropriate fixation and dehydration of the resin-bonded dentin samples, a scanned focused ion-beam of a few tens of nano-meters in diameter was used to cross-section the resin-dentin interface. Examination of the interfacial ultrastructure was accomplished using a field-emission SEM. Results . Results indicate possible artifact production at the cross-sectioned interface, hiding its actual ultrastructure, probably due to a heat-effect with possible recrystallization. Further studies of FIB are needed to optimize its usefulness for resin-dentin interface examinations and other biological tissue applications. Significance . Complete resin saturation of the demineralized dentin surface-layer has been claimed to be the key factor for a long-lasting resin-dentin bond. A “clean” artifact-free micro-cross-sectioning technique may provide indisputable ultra-structural information about the depth of resin penetration into the demineralized zone. Such a test would be useful in the development of dentin adhesive systems.

This paper presents the research results of the morphology of subsurface damage (SSD) in BK7 glass ground with on-machine fabricated PCD micro tool. Grinding generated damages are assessed and characterised using bonding interface sectioning technique combined with field emission scanning electron microscopy (FESEM). Both the damage depth and surface roughness are found to be influenced by the depth of cut, feed rate and spindle speed. Two major type of grinding damage have been identified likely chipping damage and micro-cracking damage. Lateral, median and cone cracks are found to be existed in the sub-surface. These crack size varies from below to above 1 μm. The mechanism of damage nucleation and propagation are discussed also. Although the machined surface seems to show ductile mode behaviour even at higher material removal, analysis of subsurface damage shows that the material removal is a combined effect of grain dislodgement, micro-cracking and plastic deformation.

The electron spin resonance (ESR) technique was used to investigate the diffusion of Fe 3+ in rutile (TiO 2 ). ESR absorption intensity was measured for several annealing times and three different temperatures of isothermal annealing: 1273, 1323 and 1373 K. The activation energy for diffusion, calculated from the experimental data using a theoretical model based on the Fick equation, was found to be E A = 215 kJ mol −1 . This result is consistent with experimental data using the radioactive-tracer sectioning technique and represents an independent measurement of the activation energy for diffusion of trivalent iron in rutile, which is difficult to achieve by other means in this mixed-valence system.

Using the tracer-standard sectioning technique the impurity diffusion of indium in copper has been investigated in the temperature range from 798.1 to 1081.0°C. For the frequency factor and the activation energy, respectively, the following values were determined: D02 = 1.87 cm2 · s−1; Q2 = 2.034 eV. The results are compared with predictions of theoretical models of the impurity diffusion in metals. Mit Hilfe der Tracer-Standardschichtenteilungstechnik wurde die Fremddiffusion von Indium in Kupfer im Temperaturbereich von 798,1 bis 1081,0°C untersucht. Fur den Frequenzfaktor bzw. die Aktivierungsenergie wurden folgende Werte ermittelt: D02 = 1,87 cm2 · s−1; Q2 = 2,034 eV. Bei einem Vergleich der Ergebnisse mit theoretischen Modellen fur die Fremddiffusion in Metallen zeigt sich eine gute Ubereinstimmung zwi-Theorie und Experiment.

Tracerdiffusion coefficients of Ni2+ and Ga3+ have been measured in Ni 1− y Ga 2+2 y 3 O 4 spinel solid solutions at 1585°C in air using a standard sectioning technique. The results are in good agreement with theoretical considerations assuming a vacancy mechanism for diffusion in the cation deficit region (y > 0) while both the vacancy and the interstitial mechanisms are operating within the range of cation excess (y

The diffusion of Ce ions in AgCl has been measured by the tracer and serial sectioning technique. The temperature dependence of the diffusivity follows a linear Arrhenius law with parameters D 0 =1.10×10 −3 cm 2 /s and H =0.62 eV. It appears that Ce enters the lattice as +3 ion in substitutional sites and diffuses as an associated complex with cation vacancies. The results of the study of eiectrical conductivity of the pure and Ce-doped AgCl supports this general view. Alternate possibilities are also discussed.

The diffusion of cobalt and copper in Monel-400 has been studied by serial sectioning technique using the radioactive tracers 60Co and 64Cu in the temperature ranges 1070 to 1570 K for volume diffusion and 700 to 1100 K for grain-boundary diffusion, respectively. The volume diffusion coefficients can be expressed as: for Co in Monel-400 (1070–1570 K) DCo = 3.09 × 10−4exp(−260.1 kJ/molRTm2/s, for Cu in Monel-400 (1070–1570 K) DCu = 2.88 × 10−4exp(−270.8 kJ/molRTm2/s. The grain-boundary diffusion coefficients were evaluated for most of the experiments by Whipple's method. For a few experiments Suzuoka's method was also applied. The two methods yielded values of grain-boundary diffusion coefficients that were in good agreement with each other. The grain-boundary diffusion coefficients could be represented by the expressions: for Co in Monel-400 (700–1100 K) Dgb,Co = 3.24 × 10−5exp(−151.0kJ/molRT) m2/s, for Cu in Monel-400 (700–1100 K) Dgb,Cu = 1.13 × 10−4exp(165.8kJ/molRT) m2/s, Autoradiographic technique was also used extensively to study the segregation of the diffusing tracers. It was observed that for small-grained specimens (average grain dia ~ 200 μm) at temperatures above ~ 1000 K both volume and grain-boundary diffusion processes contribute significantly to the penetration of tracer atoms in the bulk of the solid, but at lower temperatures (< 960 K) the migration is mainly through the grain boundaries.

The diffusion of gold in gamma uranium has been measured using a radioactive tracer and the sectioning technique. The values of D o and the activation energy are 4.86 × 10 −3 cm 2 /sec and 30 400 cal/mol respectively, fairly close to the values for self-diffusion in gamma uranium.

Der Reihenentwicklungskoeffizient zweiten Grades ist ein brauchbares Mas fur die Einschatzung des Fehlers experimentell bestimmter Polfiguren kubischer Materialien. Die Fehlerkoeffizienten hoheren Grades ermoglichen auserdem die Trennung der systematischen von den statistischen Fehlern. Es wurden vierzig in der Literatur angegebene Polfiguren untersucht. Die aus rontgenographischen Durch- und Ruckstrahlmessungen kombinierten Polfiguren weisen im allgemeinen wesentlich hohere Fehler auf als Messungen an Kugel- oder Zylinderproben, Proben mit Schraganschliff sowie Neutronenbeugungsmessungen. The second order coefficient of an expansion into a series is a usefull measure of the error of an experimentally determined pole figure. The higher order error coefficients may be used to distinguish between systematic and statistic errors. Fourty pole figures, published in the literature, have been analysed. Pole figures measured by a combined transmission and reflection technique exhibited the highest level of error. Those measured with zylindrical or spherical specimen, by the oblique sectioning technique or by neutron diffraction are much better.

Forced by the progressive perfectionation of the ultramicrotomes and by the improvement of preparation methods, the ultrathin sectioning technique has gained high importance for the electron-microscopical studies of the fine structure of wood cell walls. Wood has its own problems for ultramicrotomy. During cutting, the inhomogeneity of the cell wall and its chemical nature result in the formation of wrinkles and holes in the ultrathin sections. These artefacts are not completely avoidable but can be reduced by suitable embedding and by choosing the most suitable knife to a minimum. It is pointed out that for the best and most reliable statement on the object the cutting of serial sections is indispensable.

Electron microscopic studies of thin sections of industrial carbons have been extended to green mixes. Pitch is shown to have discrete spherical bodies (0.5–1.0 μ) distributed in a continuous medium. A dissolution technique is described which distinguishes the coke from the binder in a green mix. The results suggest that the coke particles have an irregular three-dimensional porous structure and the apparent inability to observe particles larger than a few microns is explained. The sectioning technique leads to morphological features comparable to those seen by replication.

Submicron sectioning apparatus for studying slow carbon self diffusion in dense polycrystalline tungsten carbide

Diffusion of 54 Mn in Mn 1−δ O single crystals has been measured by a serial sectioning technique as a function of temperature (1000–1500°C) and deviation from stoichiometry (0.00003 m in the expression D = D 0 (T)p O 2 1 m varies from about 6 at low P o 2 at all temperatures to a value approacing 2 at high P o 2 and high temperatures, thus suggesting that diffusion occurs by doubly charged vacancies at low P o 2 with increasing contributions from singly charged and neutral vacancies as P o 2 (and vacancy concentration) increases. For δ near 0.1, the values of D fall below the values extrapolated from smaller defect concentrations. The isotope effect for cation self-diffusion was measured by simultaneous diffusion of 52 Mn and 54 Mn in Mn 1−δ O (0.0004 f ΔK are independent of temperature within experimental error, and decrease from a value of 0.70 at low defect concentrations to 0.37 for large values of δ. The isotope-effect results suggest that diffusion occurs by single non-interacting vacancies at low defect concentrations; defect-defect interactions become important for δ ≳ 0.01. The defect-defect interactions may involve essentially individual defects or may result in defect clusters; the similarity between the present isotope-effect results and those for Fe 1−δ 0 suggests that defect clustering plays a significant role in mass transport in Mn 1−δ O at large values of δ.