Process Of Texture Formation Research Articles

Microstructure, domain structure, ferroelectric and piezoelectric properties of textured bismuth-containing ceramics

In this report, the processes of texture formation in grain-oriented ferroelectric ceramics based on layer-structured ferroelectric Bi4Ti3O2 (LSBT) prepared by hot forging method are considered. The microstructural and X-ray methods revealed the axial textured formation in ferroelectric ceramic that are used to estimate the orientation factor of ceramics. For the first time, the domain structure changes when poling the anisotropic ferroelectric ceramics are investigated. The anisotropy of electromechanical, piezoelectric and ferroelectric properties of ferroelectric ceramics due to the crystal texture existence in it is studied. The aim of this study is to study the processes of crystalline texture formation in polycrystalline BLSF and to establish the dependence of the electrophysical properties of ceramics on the degree of texturing. Ceramics were textured using the hot stamping (HS) method developed at the Research Institute of Physics. The mechanism of the method is that the workpiece is subjected to uniaxial pressure and free radial deformation occurs due to the plastic flow of the material until the workpiece fills the free volume of the mold, which is created by placing the workpiece in the mold with a gap. The study of the microstructure of ceramics showed that an increase in the firing temperature in the range 950–1050[Formula: see text]C causes a sharp decrease in porosity and increases the density to 7.95 g/[Formula: see text], which is 98% of theoretical. An X-ray analysis was performed and microstructural studies were carried out, which revealed the formation of an axial texture in ceramics. The features of the switching processes of textured ceramics are revealed. The characteristics of the polarization switching of ceramics in the directions parallel and perpendicular ([Formula: see text]) of the pressure axis during hot processing were obtained from the dielectric hysteresis [Formula: see text]([Formula: see text]) loops, i.e., axis axial texture. The [Formula: see text]-cut ceramics are characterized by a more complete polarization switching, which is associated with the additional orientation of the (001) crystallographic planes in the textured material, as well as the presence of a threshold switching field. In the temperature range from -196 to + 600[Formula: see text]C, the anisotropy of the electro physical properties of ceramics due to the presence of a crystalline texture in it was studied. The dielectric constant, electrical conductivity, piezoelectric and elastic coefficients were measured for sections of ceramics of different orientations relative to the axis of the texture. The anisotropy of the dielectric constant and electrical conductivity manifests itself weakly at room temperature and increases sharply when approaching the Curie temperature. In the temperature range +20–400[Formula: see text]C, the high thermal stability of the piezoelectric module [Formula: see text], measured by the quasistatic method, was established.

Structure and texture in rolled Fe82Ga18 and (Fe82Ga18)99B1 alloys after annealing under high magnetic field

The structure and crystallographic texture formation processes in two Fe–Ga magnetostrictive alloys during annealing of deformed samples under high magnetic field (HMF) 20 T have been studied. It was shown that the effect of the magnetic field on the structure transformation during annealing depends on the features of the recrystallization in alloys. In the case of recrystallization in a single-phase binary Fe-Ga alloy, the application of HMF along the rolling direction promotes the formation of <100> grains along this direction. This leads to a twofold increase in the magnetostriction of the polycrystalline sample. In the same alloy, but with the presence of particles of the second phase, HMF does not affect the texture. The reasons for this phenomenon were discussed. In addition, it was found that in both alloys, the application of HMF during annealing retards the processes of structure evolution.

Crystallographic Texture and Applications of Pure Cu Formed by Shot Peening

The crystallographic texture of pure Cu formed by shot peening (SP) and the texture formation process are investigated. When a pure Cu sheet with a β‐fiber texture is subjected to SP, grain refinement occurs and a deformation‐induced layer is formed around the peened surface. The crystal lattice is rotated and a {110} fiber texture, in which the ⟨110⟩ direction is parallel to the plane normal direction of the peened surface, is formed. The intensity of the {110} fiber texture increases with increasing SP duration. The {110} fiber texture is formed by uniaxial compression for face‐centered cubic metals. It is concluded that uniaxial compression is dominant in deformation by SP and a {110} fiber texture is therefore formed. Moreover, using shot‐peened (SPed) specimen with {110} fiber texture, a growth test of graphene is carried out. The SPed specimen is used as a substrate to grow the graphene by the chemical vapor deposition process. Growth of high‐quality graphene on the SPed specimen is obtained compared to unprocessed substrate surface. Therefore, control of the crystallographic texture by SP would be one of important tools for preparing Cu and other catalytic substrate surfaces for high‐quality graphene growth.

Microstructure and crystallographic structure of ferritic steel subjected to stress-corrosion cracking

The article presents the results of studies on the microstructure and crystallographic texture of ferritic steel under stress-corrosion cracking (SCC). Using scanning electron microscopy (SEM), the size and type of non-metallic inclusions, the elemental composition of corrosion products, and the cracking mode in the SCC zone were determined. As a part of X-ray diffraction (XRD) analysis, during which the shape and size of grains-crystallites, crystallographic texture, atomic displacements, the Debye-Waller factor and instrumental broadening of lines using the Caliotti function for LaB6 were taken into account, parameters of the microstructure in the SCC zone were assessed. It is shown that the SCC zone is characterized by high density of introduced edge-type dislocations, strong elastic microdistortions of the crystalline lattice and a relatively small size of coherent scattering domains (CSD). It is found that the processes of texture formation in the pipeline during SCC are characterized by a set of Cube {001}<100>, Brass {110}<11¯1>, Copper {112}<1¯11¯>, rotated copper H {001}<11¯0>, Goss {001}<110> and СН {001}<21¯0> orientations. It is shown that when approaching the zone where there are no SCC traces, orientations of Goss {001}<110>, Copper {112}<1¯11¯> and Rot G {011}<01¯1> type increase and orientations of Cube {001}<100>, H {001}<11¯0> and СН {001}<21¯0> type decrease.

Моделирование кристаллографической текстуры феррит / мартенситной стали при прокатке: уровень и анизотропия прочностных свойств

This paper presents the results of studies of the level and anisotropy of strength properties in ferritic / martensitic steel during warm rolling based on the data on crystallographic texture. The features of texture formation processes in the initial and UFG samples subjected to flat rolling are analyzed by the method of texture analysis and computer modeling. In particular, the analysis of the orientation distribution function (ODF) made it possible to establish the change in the main preferential orientations (Brass, Goss, Copper, Cube, TC, Y, Z and Rotated Cube) depending on the degree of reduction. It is shown that in flat rolling, a stable rolling texture is formed only after 70 % reduction, at which H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> orientations become the main ones. At high degrees of flat rolling, the sharpness of the above textural maxima increases, which is accompanied by the activation of a smaller number of slip systems, and the misorientations between adjacent grains become predominantly high-angle ones. Within the framework of modeling of crystallographic textures, deformation mechanisms were established, two-dimensional projections of yield contours, Young's module and Lankford coefficients (r-value) were constructed. In particular, the results of computer simulation of the yield contours of steel after tempering the coarse-crystalline and UFG states showed that at low degrees of flat rolling reduction, an increased level of anisotropy of strength properties is associated with the residual crystallographic texture in the workpiece, and an increase in the degree of flat rolling leads to alignment of the strength anisotropy in sheets. It was found that the quantitative ratio of the main textural components of the type H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> during rolling determine the anisotropy of the strength properties of steel.

The downregulation of PpPG21 and PpPG22 influences peach fruit texture and softening.

The downregulation of PpPG21 and PpPG22 expression in melting-flesh peach delays fruit softening and hinders texture changes by influencing pectin solubilization and depolymerization. The polygalacturonase (PG)-catalyzed solubilization and depolymerization of pectin plays a central role in the softening and texture formation processes in peach fruit. In this study, the expression characteristics of 15 PpPG members in peach fruits belonging to the melting flesh (MF) and non-melting flesh (NMF) types were analyzed, and virus-induced gene silencing (VIGS) technology was used to identify the roles of PpPG21 (ppa006839m) and PpPG22 (ppa006857m) in peach fruit softening and texture changes. In both MF and NMF peaches, the expression of PpPG1, 10, 12, 23, and 25 was upregulated, whereas that of PpPG14, 24, 35, 38, and 39 was relatively stable or downregulated during shelf life. PpPG1 was highly expressed in NMF fruit, whereas PpPG21 and 22 were highly expressed in MF peaches. Suppressing the expression of PpPG21 and 22 by VIGS in MF peaches significantly reduced PG enzyme activity, maintained the firmness of the fruit during the late shelf life stage, and suppressed the occurrence of the "melting" stage compared with the control fruits. Moreover, the downregulation of PpPG21 and 22 expression also reduced the water-soluble pectin (WSP) content, increased the contents of ionic-soluble pectin (ISP) and covalent-soluble pectin (CSP) and affected the expression levels of ethylene synthesis- and pectin depolymerization-related genes in the late shelf life stage. These results indicate that PpPG21 and 22 play a major role in the development of the melting texture trait of peaches by depolymerizing cell wall pectin. Our results provide direct evidence showing that PG regulates peach fruit softening and texture changes.

Formation of crystallographic texture in Fe-Ga alloys during various types of plastic deformation and primary recrystallization

The regularities of texture formation in FeGa-based alloys during deformation at medium degrees (about 60 %) and primary recrystallization were studied. Deformation was realized by two methods: rolling and hydrostatic extrusion to study the deformation behavior and the texture formation processes. After deformation, the samples were subjected to annealing to initiate primary recrystallization. The structure and texture after deformation and recrystallization were studied using EBSD technique. It was shown that FeGa-based alloys have a greater tendency to form {hkl}<100> texture during primary recrystallization, compared to other wide-used soft magnetic materials with body-centered cubic (bcc) lattice. Alloying by boron enhances this tendency and results in a uniform texture after recrystallization. As a result, a high level of functional properties was achieved through the implementation of cost-effective deformation and annealing operations.

Formation of Recrystallization Cube Texture in Highly Rolled Ni–9.3 at % W

In this work the formation of strong recrystallization cube texture in heavily rolled Ni–9.3 at % W has been studied. During the cold rolling (also known as recovery-rolling) process the deformation texture of Ni–9.3 at % W alloy (further notated as Ni9W) transforms to Copper-type rolling texture, and after annealing, a sharp cube texture is generated. It is remarkably strong recrystallization cube texture, as high as 93 vol %, in metallic materials with low stacking fault energy. The formation mechanism of the cube texture is adopted for the rapid recovery of cube nuclei at the early stage of recrystallization as well as fast migration rate of high angle boundaries between cube grains and deformed microstructure at high temperature. Considering the cold rolling texture of Ni9W, oriented nucleation seems to play more important role in the cube texture formation process. In this article, the relationship between the deformation texture and recrystallization cube texture is discussed.

Texture formation process of 6063-type aluminium alloy during hot extrusion

This study investigated the texture formation process of A6063 alloy hot extruded material using electron backscatter diffraction (EBSD) measurements. The cube component that becomes the main orientation during hot extrusion was formed near the bearing inflow in the extrusion chamber and grew with continuous recrystallization. The Goss component with the same ED // &lt;100&gt; relationship as the cube component was not formed in the chamber or the bearing but was formed by discontinuous recrystallization after passing through the bearing. The TD // &lt;111&gt; orientation component of the surface layer was formed in the bearing and then grew with discontinuous recrystallization. However, because the internal cube and Goss components expanded preferentially, the surface layer TD // &lt;111&gt; components were replaced by the cube and Goss components after passing through the bearing. The cubic texture formation of extruded aluminium alloys is noted to be analogous to the formation of rolling sheet materials, formed by recovery and recrystallization from a plane strain deformation structure. However, for the A6063 alloy extruded under conditions close to industrial production, the cube components were mainly formed by recovery and continuous recrystallization.

FEATURES OF FORMATION OF CRYSTALLOGRAPHIC TEXTURE AND PROPERTIES IN Ti-3Al-2.5V TITANIUM ALLOY DURING TUBES MANUFACTURE

Texture formation processes at all technological stages of tube manufacture were considered. It has been established that at the stage of hot deformation and manufacture of TREX tubes, tangential and radial textures are formed, a large share of tangential component of the texture. Influence of main factors of the technological process on formation of texture and properties was established. Conditions for formation of a maximum amount of radial texture in tubes which ensure improvement of service properties of tubes were determined. To create maximum amount of radial texture in tubes, total reduction rate in passes and the wall to diameter reduction ratio (factor Q) are important. The reduction rate should be increased, especially in the last passes, to 75…85%. Heat treatment (stress relief annealing) practically does not change the tube texture.

Modeling the Cryogenic Texture Formation Process in the Soil Around the Pipeline

This article is concerned with the study and analysis of heat exchange processes, moisture transfer and cryogenic texture formation in fine dispersed soils when laying and operating underground pipelines. The segregation frost heaving around cold big-diameter pipelines buried in the soil has been investigated. The method of modeling the secondary frost heaving is presented. The conditions under which this model is applicable as a result of assumptions made during its construction are described. The model is presented in a stringent mathematical formulation. The checking numerical case has been calculated. The process of ice layers formation graph is given. Under certain conditions one layer can be formed and under the other conditions two layers can be formed. Mostly it depends on the pipe temperature. For this case the guidelines for soil frost heaving prevention are given. The guidelines are general and applicable to other cases.

Microstructure and Texture of Ni7W/Ni12W/Ni7W Composite Substrates at Different Intermediate Annealing Temperatures

Ni7W/Ni12W/Ni7W composite substrates for YBa2Cu3O7-δ coated conductors were prepared by rolling assisted biaxially textured substrates route. A threefold intermediate annealing at different temperatures was introduced in the rolling process of Ni7W/Ni12W/Ni7W composite substrates to optimize the deformation texture. The recovery microstructure and the deformation texture of latitude and longitude section were studied with X-ray diffraction and electron backscattered diffraction to reveal the possible mechanism of temperature effects on rolling and strong cube texture formation processes. The results show that the highest cube area fraction is found in sample intermediately annealed at 600 °C/60 min; in this way Ni7W/Ni12W/Ni7W composite substrates with high cube texture content of 95% (<10°) are obtained at a low recrystallization annealing temperature. Crystal orientation maps reveal that a higher amount of cube orientation exists in its recovery and initial recrystallization samples. Point to point misorientation files confirm the high grain boundary angle of these cube grains, which strongly boost the cube texture formation during subsequent recrystallization.

Study on microstructure evolution of AISI 304 stainless steel joined by rotary friction welding

The object of the present work is to research the microstructure evolution of AISI 304 stainless steel (304SS) joined by rotary friction welding. The dynamic recrystallization (DRX) and texture formation process were analyzed by optical microscope and electron back-scattered diffraction (EBSD) technology. The results showed that DRX, which emerges on the torque rising stage, mainly occurs in the welding zone, and completes on the torque quasi-steady stage. Furthermore, obvious shear type texture ({110} ) forms in the joint of 304SS.

Features of Formation of Crystallographic Texture in Cells of Spacing Grid at their Stamping

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Structural aspects of the phase and texture formation processes in thin-layer Ni-W/TiN systems which are perspective for creating high-temperature superconductors of the second generation

Structural aspects of the phase and texture formation processes in thin-layer Ni-W/TiN systems which are perspective for creating high-temperature superconductors of the second generation

Formation process of the {001} fiber texture on iron particles using simple ball milling

The process of texture formation on iron particles was investigated via simple ball milling using graphite particles as milling aid. During milling, the shape of the iron particles changed from granular to platelets owing to repetitive compression and balls rolling in a direction perpendicular to the platelet faces. Simultaneously, a {001}+{111} double-fiber texture was formed, which is characteristic of a metal with a bcc structure deformed under uniaxial compression and multidirectional rolling. Based on these observations, it is concluded that the texture obtained through simple ball milling was induced by uniaxial compression and a multidirectional-rolling-like deformation. Since the main component of the double-fiber texture is {001} and the easy magnetization axes 〈001〉 are oriented toward the in-plane directions with the platelet face in the texture, the iron particles are ideal candidates for use as magnetic cores in motors, inductors, and other electromagnetic parts.

Research on processes of texture formation in "NiW substrate and TiN coating" system and creation of the new type textured paramagnetic substrates for HTS based on YBa&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;7&lt;/sub&gt;

Research on processes of texture formation in "NiW substrate and TiN coating" system and creation of the new type textured paramagnetic substrates for HTS based on YBa&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;7&lt;/sub&gt;

The mechanism of texture formation during crystallization process of Ge2Sb2Te5 thin films

In this work, we determined the grain growth mode and texture formation process experimentally and theoretically in crystallization process of Ge2Sb2Te5 thin films, which were prepared by ion beam sputtering using Ge2Sb2Te5 alloy target. Experiment results demonstrated that crystalline grains had a trend of island growth during annealing, the texture components of cube {100}&lt;001&gt; and rotation cube {100}&lt;011&gt; are present in 250 °C annealed thin films, and {0001} basal texture component was produced in 400 °C annealed thin films. Theoretical analysis proved the mechanism and driving forces of grain growth and cubic texture formation: grains gathered in the basal surface as island because of large lattice mismatch, meanwhile, the preferred orientation of thin films was triggered by the minimization of lattice mismatch strain energy. The calculation results were in conformance with the experimental results. Researches about grain growth mode and texture formation of Ge2Sb2Te5 thin films may provide an advice to increase the crystallization rate of phase change material.

Creation of a sharp cube texture in ribbon substrates of Cu–40% Ni–M (M = Fe, Cr, V) ternary alloys for high-temperature second generation superconductors

The structure and the process of texture formation in ribbons made of Cu–Ni–M (M = Fe, Cr, V) ternary alloys have been studied upon cold rolling deformation to a degree of ~99% and subsequent recrystallization annealing. The possibility of obtaining a perfect cube texture in a thin ribbon made of copper–nickel-based ternary alloys with additives of iron, chromium, and vanadium has been shown, which opens the prospects of the use of these alloys as substrates in the technology of production of tapes of high-temperature second-generation superconductors. Optimal annealing regimes have been determined, which make it possible to obtain a perfect biaxial texture close to single-crystalline one with the content of cube-oriented grains {001}〈100〉±10° more than 99% on the surface of the textured ribbon.

Textured tape substrates made of ternary alloys based on Cu–40%Ni–Me constantan for epitaxial deposition of buffer and superconducting layers

The structure was studied and the texture formation process was investigated in tapes made of Cu–Ni–Me ternary alloys (Me = Fe, Cr, V, or Mn) during cold deformation by rolling to a degree of ∼99% with subsequent recrystallization annealing. It was shown that it is generally possible to create a perfect cubic texture in a thin ribbon made of ternary alloys based on copper and nickel to which a period 4 d-element (iron, chromium, or vanadium) was added. This makes these tapes promising as substrates in the technology for producing second-generation high-temperature superconductor tapes. The optimal annealing conditions were determined, under which, in the studied alloys, a perfect biaxial near-single-crystalline texture can be obtained with a content of cubic grains {001}〈100〉 ± 10° on the surface of the textured ribbon of above 99%.