scholarly journals Contact interaction at the composites interfaces between the microcrystalline particulate and the molten matrix

2018 ◽  
Vol 26 (2) ◽  
pp. 29-32
Author(s):  
O. V. Sukhova ◽  
Yu. V. Syrovatko
Keyword(s):  
Dissolution Rate ◽  
Structure Formation ◽  
Microcrystalline Structure ◽  
Diffusion Type ◽  
Crystalline Phases ◽  
The Matrix ◽  
Quantitative Analyses ◽  
Solid Phases ◽  
Average Size ◽  
And Diffusion

The peculiarities in structure formation of interfacial zones at the composite’s boundaries between the molten Fe–C–B–P–Mo matrix and the filler’s solid phases of W2C and WC that have microcrystalline structure were investigated in this work. The structure of the interfaces was studied by methods of metallographic and automatized quantitative analyses. The interfaces of dissolution-and-diffusion type were observed between the matrix and the filler. A dissolution rate of the filler’s microcrystalline phases of W2C and WC was shown to decrease by ~ 1.7–1.8 times as against that of the crystalline phases of the same composition. This result was explained considering the dependence of an average shift of atoms from the equilibrium positions in the lattice on linear size of the phases. Since the average size of the microcrystalline phases is ~ 25 times smaller than that of the crystalline phases, the average shift of microcrystalline phase atoms from the equilibrium positions decreases by ~ 1.7 times. Correspondingly, the microcrystalline particulate dissolves in the molten matrix at the lower rate than crystalline one which prevents from formation of undesirable brittle compounds in the structure of composite’s interfacial zones during infiltration.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

Development of the Synthetic Rock Technique for the Immobilization of Iodine: Kinetics of the Alumina Matrix Dissolution under High Alkaline Conditions

2012 ◽  
Vol 1518 ◽  
pp. 79-84 ◽  
Author(s):  
Hideaki Miyakawa ◽  
Tomofumi Sakuragi ◽  
Hitoshi Owada ◽  
Osamu Kato ◽  
Kaoru Masuda
Keyword(s):  
Dissolution Rate ◽  
Rate Constant ◽  
Base Material ◽  
Dissolution Behavior ◽  
Treatment Technique ◽  
Release Behavior ◽  
Alumina Matrix ◽  
Synthetic Rock ◽  
The Matrix ◽  
Iodine Release

ABSTRACTIodine filters expended after nuclear fuel reprocessing contain radioactive iodine (I-129), almost all of which exists as silver iodide (AgI). The synthetic rock technique is a solidification treatment technique using hot isostatic press (HIP), in which the alumina adsorbent base material is synthesized to form a dense solidified material (synthetic rock), and I-129 is physically confined in the form of AgI in the alumina matrix. Thus, it is necessary to understand the matrix dissolution behavior to evaluate the iodine release behavior.Experiments involving the dissolution of the matrix were carried out under various temperatures (35–70 °C) and pH values (10–12.5) that reflect the disposal conditions. The results of the experiments showed that the dissolution rate of Al visibly increases with temperature and pH. The dissolution rate constant was calculated from the initial data assuming the dissolution of the matrix as a primary reaction. The logarithmic rate constant showed a good linear correlation with the pH and the reciprocal of temperature. The 27Al-NMR analysis of the solutions of the dissolved matrix showed that the major chemical species present in the solutions was Al(OH)4-. This indicated that the dissolution of the matrix can be described by the following equation: Al2O3 + 2OH- + 3H2O → 2Al(OH)4-. Subsequently, the empirical equation of the rate of dissolution of the matrix as a function of the temperature and pH was derived. It will be used to evaluate the iodine release behavior from the synthetic rock.

Microstructural Stability and Lattice Misfit Characterisations of Nimonic 263

2012 ◽  
Author(s):  
Quanshun Luo ◽  
Kuangnan Chi ◽  
Shuxin Li ◽  
Pete Barnard
Keyword(s):  
Grain Boundary ◽  
Morphological Evolution ◽  
Lattice Misfit ◽  
Initial Growth ◽  
Microstructural Stability ◽  
Gaussian Peak ◽  
Hardening Treatment ◽  
The Matrix ◽  
Matrix Lattice ◽  
Average Size

Nimonic 263 has been selected as a candidate header/piping material of advanced ultra-supercritical (A-USC) boilers for the next generation of fossil fuel power plant. Experimental assessments on the microstructural stability of this material are presented in this paper. Microstructural evolution has been quantified by high resolution field emission SEM and TEM. Electron diffraction and the combined XRD and Gaussian peak-fitting have been applied to investigate the coherency and lattice misfit between the gamma prime (γ′) precipitates and the gamma (γ) matrix. The micro structure subjected to solution and hardening treatment consists of γ-matrix and a network of carbide precipitates along the grain boundaries. Large quantities of fine γ′-Ni3(Ti,Al) precipitates were observed, with an average size of 17 nm and coherent with the matrix lattice. The overall misfit has been quantified to be 0.28%. After long term aging at 700 and 725 °C for various periods up to 20,000 hours, γ′ was still the predominant precipitate and mostly coherent with the matrix. A few needle-shape η-Ni3Ti intermetallic precipitates were found in the grain boundary regions. The γ′ size has grown progressively to 78 nm, accompanied by the γ′-γ constrained misfit increasing to 0.50%. Moreover, the M23C6-type grain boundary carbides were found to have experienced morphological evolution, including the nucleation of Widmanstatten-type needles and their initial growth towards the matrix.

scholarly journals Particularities of structure formation of aluminum-copper composite materials manufactured by casting technology

2020 ◽  
pp. 116-121
Author(s):  
V. A. Kalinichenko ◽  
A. S. Kalinichenko ◽  
S. V. Grigoriev
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Structure Formation ◽  
Matrix Material ◽  
Matrix Alloy ◽  
Alloying Elements ◽  
Casting Technology ◽  
The Matrix ◽  
Reinforcing Material ◽  
Copper Composite

To create friction pairs operating in severe working conditions, composite materials are now increasingly used. Composite materials obtained with the use of casting technologies are of interest due to the possibility to manufacture wide range of compositions at low price compared to powder metallurgy. Despite the fact that many composite materials have been sufficiently studied, it is of interest to develop new areas of application and give them the properties required by the consumer. In the present work the composite materials on the basis of silumin reinforced with copper granules were considered. Attention was paid to the interaction between the matrix alloy and the reinforcing phase material as determining the properties of the composite material. The analysis of distribution of the basic alloying elements in volume of composite material and also in zones of the interphases interaction is carried out. The analysis of the possibility of obtaining a strong interphase zone of contact between the reinforcing component and the matrix material without significant dissolution of the reinforcing material is carried out.

Action and agency in complex sentences from present-day Romanian

2020 ◽  
Vol 13 (62) (1) ◽  
pp. 39-56
Author(s):  
Alice BODOC
Keyword(s):  
Natural World ◽  
Qualitative And Quantitative ◽  
Complex Sentences ◽  
The Matrix ◽  
Quantitative Analyses ◽  
Adverbial Clause ◽  
Linguistic Phenomenon ◽  
Matrix Verb

Starting from Alanen’s remark that “actions (exercises of capacities) are found throughout the natural world; and so is agency” (2018, 2), the present paper aims at describing the influence of these two fundamental concepts – action and agency – on the structure of Romanian complex sentences. More precisely, I am interested in providing evidence of a linguistic phenomenon that has received far less attention in the literature, i.e. the semantic restrictions imposed by the matrix verb over the embedded adverbial clause. As concerns the methodology, both qualitative and quantitative analyses will be conducted on an extensive online Romanian corpus (CoRoLa), and will be based on the semantic typologies of the verb included in some of the reference Romanian grammars (GALR 2008, 326; GBLR 2010, 279). One of the most important results of the analysis was the phenomenon of agentivity

scholarly journals Ductile saline ice

1994 ◽  
Vol 40 (136) ◽  
pp. 566-568
Author(s):  
G. A. Kuehn ◽  
E. M. Schulson
Keyword(s):  
Fresh Water ◽  
Tensile Ductility ◽  
Compressive Deformation ◽  
Dislocation Creep ◽  
Diffusion Creep ◽  
Water Ice ◽  
The Matrix ◽  
And Diffusion

AbstractExperiments have shown that tensile ductility of about 5% or more can be imparted to columnar, saline ice by pre-compressing the material by about 3.5%. This effect is similar to that observed in granular, fresh-water ice and is attributed to the operation of both dislocation creep and diffusion creep within that part of the matrix which recrystallized during the pre-compressive deformation.

Study of Glass-Ceramic Waste Forms

1997 ◽  
Vol 506 ◽  
Author(s):  
S.V. Stefanovsky ◽  
S.V. Ioudintsev ◽  
B.S. Nikonov ◽  
B.I. Omelianenko ◽  
T.N. Lashtchenova
Keyword(s):  
Glass Ceramic ◽  
Glass Composition ◽  
Glass Ceramics ◽  
High Level Waste ◽  
Matrix Glass ◽  
Crystalline Phases ◽  
Cell Parameters ◽  
The Matrix ◽  
High Level ◽  
Similar Unit

ABSTRACTSince the early of the 1990s the method of inductive melting in a cold crucible (IMCC) has been applied at SIA “Radon” for production of various wasteforms, including glasses and Synroc-type ceramics. Sphene-based glass-ceramics composed of glass and crystalline phases were considered as appropriate wasteform for High Level Waste immobilisation. Investigation of two glass-ceramic specimens prepared with the IMCC has been performed using optical microscopy, XRD, SEM/EDS, and TEM methods. The samples produced consist of vitreous and crystalline phases. The vitreous phase consists of two varieties of glass formed by the immiscibility of the initial melt onto two separate liquids. One of the glasses is observed as spherical microinclusions in the matrix glass. The glass of the microspheres are differed from the matrix glass composition by higher contents of Ca, Ti, Ce, Sr, Zr (or Cr), while the matrix glass contains higher amounts of Si, Al, and alkalies. The crystalline phases with sphene- and perrierite-like structures have been also occurred. Their total quantity reaches up to 50 vol.%. The synthetic perrierite has similar unit-cell parameters with its natural mineral analogs with the only exception in two-fold value of c dimension. Zr, Ce, and Sr are incorporated into synthetic sphene and perrierite, while Cs is hosted by the glass phases.

Matrix microcrystalline structure and acoustic properties of oomoldic dolograinstone

Geophysics ◽  
2018 ◽  
Vol 83 (4) ◽  
pp. MR199-MR210 ◽  
Author(s):  
Xavier Janson ◽  
F. Jerry Lucia
Keyword(s):  
Average Velocity ◽  
Uv Light ◽  
Acoustic Property ◽  
Acoustic Properties ◽  
Petrographic Analysis ◽  
Primary Control ◽  
Microcrystalline Structure ◽  
Reservoir Properties ◽  
Lower Velocity ◽  
The Matrix

Previous studies have shown that carbonate rock with rounded moldic macropores has a higher compressional velocity at a given porosity than rock with interparticle or intercrystalline porosity and high-aspect-ratio macropores. Our study of Permian dolograinstone challenges this commonly accepted result. Petrophysical and acoustic velocities were measured on 55 mini core plugs collected along an approximately 1 km long horizontal transect within a single grainstone unit having lateral changes from grainstone with dominantly interparticle porosity to grainstone with mostly moldic porosity. The studied dolograinstone samples have a large scattering of acoustic velocity (up to [Formula: see text]) at equal porosity. Some oomoldic grainstone samples have either higher velocity or significantly lower velocity than that of the intercrystalline grainstone samples. Petrographic analysis under plain light and UV light combined with mercury injection capillary pressure data and scanning electron microscopy analysis indicates that moldic samples with a lower than average velocity for a given porosity have a matrix with between 50% and 75% of the total porosity as intercrystalline microporosity between large moldic pores. Conversely, rocks with a higher than average velocity for a given porosity find a lack of micropores in the microcrystalline part of the matrix. The amount of micro- and mesoporosity in the matrix is the primary control on acoustic properties of those moldic dolograinstone samples. Therefore, the matrix microcrystalline structure can exert a stronger control on acoustic property than do the macropore types and shapes. These results indicate that using acoustic data from the subsurface to identify pore shape and reservoir properties still remains a challenge.

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