Characteristics of statistical properties of deformation defects of structural metallic materials within elastic deformations

At this paper was established result of the correlations characteristics of structural parameters of low-carbon steels during periodic loading under elastic deformations. According to the results of the research, the kinetic characteristics of the influence of the load parameter on the distribution of deformation defects of the surface layer of structural materials under elastic deformations are obtained. The regularities of the influence of elastic deformations on the distribution of discrete surface properties are revealed. Linear dependences of the parameter of distribution of discrete relief properties of the deformed surface on loading are revealed. The regularities of the influence of elastic deformations on the distribution of discrete surface properties are revealed. It is established that regardless of the type of load, the surface density of deformation defects of scattered fracture accumulates in the mother to a certain state of damage, which is characterized by the current state of density of elements of deformation defects.

Influence of hydrogen saturation on the structure and mechanical properties of Fe-17Cr-13Ni-3Mo-0.01C austenitic steel during rolling at different temperatures

Introduction. The development of hydrogen energy implies a decrease in the dependence of various human activities on fossil energy sources and a significant reduction in carbon dioxide emission into the atmosphere. Therefore, the requirements for the quality of structural materials, which have the prospect of being used for storage and transportation of hydrogen, as well as for the creation of infrastructure facilities for hydrogen energy, are increasing. Therefore, the scientific researches on the hydrogen-assisted microstructure and mechanical behavior of structural materials in various loading schemes are of great importance. The aim of this work is to establish the effect of chemical-deformation treatment, including rolling combined with hydrogen saturation, on the microstructure, phase composition, and mechanical properties of 316L-type austenitic stainless steel. Methods. Transmission electron microscopy and backscattered electron diffraction, X-ray diffraction, X-ray phase and magnetic phase analysis, microindentation and uniaxial static tension are utilized. Results and Discussion. It is shown experimentally that after rolling with 25 and 50 % upset, the morphology of the defect structure and the phase composition of 316L steel substantially depends on the deformation temperature (at room temperature or with the cooling of the samples in the liquid nitrogen) and on hydrogen saturation rate (for 5 hours at a current density of 200 mA/cm2). The main deformation mechanisms of the steel in rolling are slip, twinning, and microlocalization of plastic flow, which all provide the formation of ultrafine grain-subgrain structure in the samples. In addition, deformation-induced ε and α' martensitic phases are formed in the structure of the rolled samples. Regardless of the regime of chemical-deformation processing, grain-subgrain structures with a high density of deformation defects are formed in steel, but its morphologies are dependent on the processing regime. The experimental data indicate that both preliminary hydrogen saturation and a decrease in the deformation temperature contribute to the more active development of mechanical twinning and deformation-induced phase transformations during rolling. Despite the discovered effects on the influence of hydrogen saturation on the deformation mechanisms and the morphology of a defective microstructure formed during rolling, preliminary hydrogenation has little effect on the mechanical properties of steel at a fixed degree and temperature of deformation. These data indicate that irrespective of the morphology of the defective grain-subgrain structure, grain refinement, accumulation of deformation defects and an increase in internal stresses lead to an increase in the strength characteristics of the steel.

Plastic deformation localization study of metal-intermetallic layered composites under dynamic channel-angular pressing

The method of mathematical modeling has been used to study the processes of plastic deformation localization of layered metal-intermetallic composites under dynamic channel-angular pressing. The deformation patterns of single-phase intermetallic samples and layered composites samples with the different arrangement of layers relative to the compression axis have been compared. The calculated stress-strain curves have been obtained. Three-dimensional modeling has been carried out on the basis of an approach combining two methods for the plastic flow description through the kinetics of deformation defects storage and the solid state mechanics. The numerical solution of the model equations has been carried out by the finite element method.

Clustering Artificial Atoms Induced by High-Frequency Electromagnetic Radiation in Graphene Monolayers of Multiwalled Carbon Nanotubes

A graphene-charge carrier confinement induced by high-frequency photons and a subsequent clustering of artificial atoms in graphene plane have been studied using electrophysical and Raman-spectroscopy methods. To fabricate the graphene n-p-n junctions, commensurable superlattice structures consisting of multi-walled carbon nanotubes (MWCNTs) have been formed utilizing a Langmuir-Blodgett technique. It has been shown that the p-n graphene junctions are sensitive to graphene lattice-deformation defects only. The levels of graphene defect do not host impurity electrons. One offers a mechanism of graphene monolayer self-repairing after a radiation damage. This mechanism is based on an existence of topologically protected Compton scatterers in graphene plane.

Revisited: gas-saturated defects in titanium alloys

The simulation results of the internal defects generated during deformation by extrusion and rolling are presented herein. It was demonstrated that end-type deformation defects can result in the formation of internal gas-saturated defects not cropping out the surface under the specific deformation conditions. Key characteristics of the generated defects similar to those of the production defects that have been previously classified as metallurgical are determined. Key words: defect, deformation, discontinuity.

Analisa Kecacatan Produk Baling-Baling Blower pada Proses Chasting ­Menggunakan Metode Seven Tools di CV. Anugerah Abadi

<p>ABSTRAK<br />Terdapat lima kecacatan dalam pembuatan baling-baling blower U-8 yaitu cacat berlubang, permukaan kasar, retak, kekasaran meluas dan deformasi. Kecacatan yang dialami sebesar 1204 produk atau 20,27% dari jumlah produksi. Permukaan kasar merupakan jenis cacat yang mempunya tingkat kecacatan terbesar yaitu 53,08% dari total kecacatan atau sebanya 627 produk. Untuk mengurangi cacat produk baling-baling blower U-8 harus difokuskan pada jenis kecacatan permukaan kasar. Untuk mengurangi jenis kecacatan tersebut operator harus lebih teliti dalam melakukan pemeriksan cetakan pasir, bahan baku aluminium juga harus bersih dan sebagian dari bahan ingot (batangan), campuran pasir cetak harus diperhatikan, kondisi lingkungan harus menerapkan 5P dan menambah fasilitas kerja( lampu penerangan), pergantian alat seperti mold dan penambahan pengkur suhu pada tungku peleburan.<br />Kata Kunci: metode seven tools, cacat produk, proses produksi</p><p>Analysis of Blower Blacker Product Reality in Chasting Process <br />Using Seven Tools Method in CV. Anugerah Abadi<br />ABSTRACT<br />There are five defects in the manufacture of U-8 blower blades which are hollow defects, rough surfaces, cracks, widespread roughness, and deformation. Defects experienced by 1204 products or 20.27% of total production. The rough surface is a type of defect that has the biggest disability rate of 53.08% of the total disability or Seba 627 products. To reduce the defects of the U-8 blower products should be focused on the types of rough surface defects. In order to reduce the type of disability the operator must be more careful in examining the sand mold, the aluminum raw material must also be clean and part of the ingot material (bar), the mixture of printed and must be considered, the environmental conditions must apply 5P and add work facilities (lighting) replacement tools such as mold and the addition of temperature drier to the melting furnace.<br />Keywords: seven tools method, product defect, production process</p>

Modeling Dislocation Contrasts Obtained by Accurate-Electron Channeling Contrast Imaging for Characterizing Deformation Mechanisms in Bulk Materials

Electron Channeling Contrast Imaging (ECCI) is becoming a powerful tool in materials science for characterizing deformation defects. Dislocations observed by ECCI in scanning electron microscope exhibit several features depending on the crystal orientation relative to the incident beam (white/black line on a dark/bright background). In order to bring new insights concerning these contrasts, we report an original theoretical approach based on the dynamical diffraction theory. Our calculations led, for the first time, to an explicit formulation of the back-scattered intensity as a function of various physical and practical parameters governing the experiment. Intensity profiles are modeled for dislocations parallel to the sample surface for different channeling conditions. All theoretical predictions are consistent with experimental results.

Modeling Dislocation Contrasts Obtained by Accurate-Electron Channeling Contrast Imaging for Characterizing Deformation Mechanisms in Bulk Materials

Electron Channeling Contrast Imaging (ECCI) is becoming a powerful tool in Materials Science for characterizing deformation defects. Dislocations observed by ECCI in Scanning Electron Microscope, exhibit several features depending on the crystal orientation relative to the incident beam (white/black line on a dark/bright background). In order to bring new insights concerning these contrasts, we report an original theoretical approach based on the dynamical diffraction theory. Our calculations led, for the first time, to an explicit formulation of the backscattered intensity as a function of various physical and practical parameters governing the experiment. Intensity profiles are modeled for dislocations parallel to the sample surface for different channeling conditions. All theoretical predictions are consistent with experimental results.