The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
W. Borek - One of the best experts on this subject based on the ideXlab platform.
-
Thermo-Mechanical Treatment of Fe-Mn-(Al, Si) TRIP/TWIP steels
Archives of Civil and Mechanical Engineering, 2012Co-Authors: L. A. Dobrzański, W. BorekAbstract:Recent development in group of Fe-Mn-Al-Si steels with high-manganese content demands for more research in thermo-Mechanical Treatment and development of micro-structure in such steels. Hot working conditions on forming the structure and course of the heat activated processes, removing the strain hardening effects, have been investigated. The chemical compositions of two high-manganese austenitic TRIP/TWIP steels containing various Mn concentrations were developed. Additionally, the steels were microalloyed by Nb and Ti in order to control the grain growth under hot-working conditions. The force-energetic parameters of hot-working were determined in continuous and multi-stage compression test performed in temperature range from 850 to 1100 °C and strain rate of 0.1, 1, 10 s^−1 using the Gleeble 3800 thermo-Mechanical simulator. The microstructure of investigated steels was determined in metallographic investigations using light microscope as well as X-ray diffraction. It was found that the thermo-Mechanical Treatment conditions have no influence on phase composition of the investigated steels.
-
thermo Mechanical Treatment of fe mn al si trip twip steels
Archives of Civil and Mechanical Engineering, 2012Co-Authors: L A Dobrzanski, W. BorekAbstract:Abstract Recent development in group of Fe–Mn–Al–Si steels with high-manganese content demands for more research in thermo-Mechanical Treatment and development of microstructure in such steels. Hot working conditions on forming the structure and course of the heat activated processes, removing the strain hardening effects, have been investigated. The chemical compositions of two high-manganese austenitic TRIP/TWIP steels containing various Mn concentrations were developed. Additionally, the steels were microalloyed by Nb and Ti in order to control the grain growth under hot-working conditions. The force-energetic parameters of hot-working were determined in continuous and multi-stage compression test performed in temperature range from 850 to 1100 °C and strain rate of 0.1, 1, 10 s −1 using the Gleeble 3800 thermo-Mechanical simulator. The microstructure of investigated steels was determined in metallographic investigations using light microscope as well as X-ray diffraction. It was found that the thermo-Mechanical Treatment conditions have no influence on phase composition of the investigated steels.
S N Kulkov - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Mechanical Treatment on the Structure and Properties of Natural Zeolite
Inorganic Materials: Applied Research, 2018Co-Authors: Alexandr Y. Buzimov, S N Kulkov, László A. Gömze, R. Géber, István KocserhaAbstract:The morphology, specific surface area, structure, and phase composition of natural zeolite powder from the Tokai deposit which underwent Mechanical Treatment in a planetary mill was studied using the following methods: scanning electron microscopy (SEM), X-ray structural analysis, Brunauer–Emmett–Teller (BET) method, laser diffraction, and elemental analysis. The identification of natural zeolite X-ray patterns showed that the powder consisted of seven phases with different contents of minerals: smectite, quartz, cristobalite, clinoptilolite, illite, orthoclase, and calcite. Initially, the average size of the zeolite particles was 27 μm; after the Treatment for 20 min, it was 5.5 μm; and after 600 min, it was 28 μm. Moreover, most of the particles lost their initial shape during the Mechanical activation and acquired a spherical shape. It was shown that, during the first 60 min of Mechanical Treatment in the planetary mill, powder particles were ground, and the specific surface area increased to 33 m2/g. The further Mechanical activation was determined by agglomeration of particles and a decrease in the specific surface area. The X-ray structural analysis showed that the studied powder consisted of four phases: hexagonal, monoclinic, orthorhombic, and tetragonal modifications. Mechanical Treatment of natural zeolite led to the decrease in the coherent scattering regions and to the growth of microdistortions of the crystal lattice. It was shown that the continuous Mechanical effect on zeolite led to the increase in the amount of an amorphous phase in the powder from 13 to 52%. The changes in the specific surface area determined by the BET method and calculated from the coherent scattering region (CSR) had the same character, and the phase composition determined the specific surface area of natural zeolite.
-
Mechanical Treatment of ZrB 2 –SiC Powders and Sintered Ceramic Composites Properties
Proceedings of the Scientific-Practical Conference "Research and Development - 2016", 2017Co-Authors: S. P. Buyakova, A. G. Burlachenko, Yu. Mirovoi, Anna G. Knyazeva, S N KulkovAbstract:The effect of Mechanical Treatment by planetary ball milling on the properties of hot pressed ZrB2–SiC ceramics was studied. It has been shown that material densification after Mechanical Treatment is finished on initial stages of sintering process. Addition of SiC leads to essentially increasing of sample density up to 99% of a theoretical one for powder with 20% SiC, as compared with ZrB2 not higher when 76%. It has been shown that all defects which were accumulated during Mechanical Treatment are annealed during hot pressure process and there are no any changes of coherently diffracting domain (CDD) values in sintered ceramics. The model was suggested to describe of three-layered porous composite synthesis at the conditions of hot isostatic pressing and investigate the porosity evolution during synthesis. Model takes into account the conjugate heat exchange between sintered materials and walls of the reactor.
-
The influence of ZrB2-SiC powders Mechanical Treatment on the structure of sintered ceramic composites
IOP Conference Series: Materials Science and Engineering, 2016Co-Authors: S. P. Buyakova, A. G. Burlachenko, Yu. Mirovoi, I. Sevostiyanova, S N KulkovAbstract:The effect of Mechanical Treatment by planetary ball milling on the properties of hot pressed ZrB2 - SiC ceramics was studied. It was shown that material densification after Mechanical Treatment is finished at initial stages of sintering process. Addition of SiC leads to an essential increase of sample density to 99% of theoretically achievable for powder with 2% of SiC, as compared with ZrB2 with the density less than 76%. It was demonstrated that all defects that were accumulated during Mechanical Treatment are annealed during hot pressing, and there are no changes of CDD values in sintered ceramics.
Shufeng Yang - One of the best experts on this subject based on the ideXlab platform.
-
Evolution of oxide inclusions in stainless steel containing yttrium during thermo-Mechanical Treatment
Journal of Materials Research and Technology, 2020Co-Authors: Xueliang Zhang, Shufeng YangAbstract:Abstract To get more fundamental information on the control of rare earth inclusions in solid steel, the evolution behavior of oxide inclusions during thermo-Mechanical Treatment of stainless steel containing yttrium at 1423 K (1150 °C) was investigated in detail. Homogeneous spherical SiO2–MnO–Al2O3–Y2O3 inclusions were observed in the as-cast steel. After thermo-Mechanical Treatment, the homogeneous oxide inclusions changed to heterogeneous ones with gray-colored (SiO2–Y2O3)-rich phase and dark-colored MnO–Cr2O3–Al2O3 spinel phase owing to the mutual effects of (i) crystallization of the glassy oxide and (ii) reaction between inclusions and steel matrix. In addition, the oxide inclusions were elongated along the deforming direction of steel during hot deformation process. With increasing reduction of the steel, the MnO–Cr2O3–Al2O3 spinel phase (dark phase) were crushed into small pieces. And the two phases (gray and dark phases) in inclusions gradually became separated from each other due to different deformability. The deformation index of inclusions gradually decreased with an increase in the deformation degree of the steel, indicating that the deformability of inclusions got worse.
Alfred X. Trautwein - One of the best experts on this subject based on the ideXlab platform.
-
Study of the changes in the magnetic properties of stainless steels under Mechanical Treatment
Hyperfine Interactions, 2016Co-Authors: R. Iankov, V. Rusanov, Daniela Paneva, Ivan Mitov, Alfred X. TrautweinAbstract:Six types of stainless steels (SS) were studied for changes in its structure and magnetic properties under Mechanical Treatment. Depending on intensity and duration of the process of plastic deformation and the SS type the paramagnetic austenite structure transforms partially to completely into ferrite structure with ferromagnetic behaviour. Some of the SS tested were found slightly modified yet in the process of its manufacturing. Only one SS type with high Ni content preserved its structure and paramagnetic properties even after very intense Mechanical Treatment.
Olli Joutsimo - One of the best experts on this subject based on the ideXlab platform.
-
Effect Of Mechanical Treatment On Softwood Kraft Fiber Properties
2008Co-Authors: Olli JoutsimoAbstract:The aim of this work was to gain a better understanding of the changes occurring in softwood strength properties and fiber wall structure after Mechanical Treatment was applied to the chip/fiber matrix during kraft cooking. Mechanical Treatment of fibers during industrial and laboratory production of pulp is common. In the pulp mill the pulp is mixed, pumped and shear forces are applied to the fiber at different temperatures and under different chemical conditions. The main objective of this research was to investigate the reasons for fiber strength loss and to examine the changes that really affect fiber strength. Fiber damage, changes in the fiber wall structure, reduced single softwood kraft fiber strength and fiber deformations (curl, kinks and dislocations) all affected the fiber network properties. Mechanical Treatment at the end of kraft cooking conditions resulted in fiber damage such that single fiber strength was reduced. This increased with increasing Treatment temperature. It was concluded that both Mechanical Treatment at the end of cooking and homogenisation at room temperature of kraft pulp fibers increased the number of fiber deformations. The increase in fiber deformations did not reduce single fiber strength but did affect the strength properties of the fiber network. The fiber damage induced by Mechanical Treatment also decreased the z-directional strength of the fiber network, which was concluded to be due to separation of the structural elements on the fiber surface layer. The separation of structural elements could enhance the irregularities on the fiber surface layer and so reduce the bonding area. The bulking of the fiber surface layer, e.g. more separated layers, might reduce the ability to resist z-directional stresses. The effect of Mechanical Treatment on spruce fibers was more severe than on the corresponding pine fibers. The spruce fibers developed more deformations and damage as a result of Mechanical Treatment. The reasons for the lower bonding and strength properties of the damaged fibers could be due to differences in the fiber wall structures of spruce and pine. Overall the results suggested that fiber damage induced by Mechanical Treatment during cooking changed the fiber wall pore structure in such a way that the number of links (between fibrill aggregates) in the fibril (aggregate) skeleton of the fiber wall decreased. The reduced contact in the fibril aggregate skeleton of the fiber wall (because of fewer restrictions) affected the cell wall structure so that it could no longer support stresses in the fiber network. The zero-span tensile strength of fibers was not dependent on the degree of fiber deformation, but according to the hypothesis presented above, on the 3-dimensional arrangement of the structural elements in the fiber wall. This 3-dimensional arrangement of the structural elements in the fiber wall defines the axial load bearing ability of the softwood kraft fiber. CONTENTS PREFACE LIST OF PUBLICATIONS AUTHORS CONTRIBUTION
-
The effect of Mechanical Treatment on softwood kraft pulp fibers. Fiber wall
2005Co-Authors: Olli Joutsimo, Leif RobertsenAbstract:In an earlier study the authors found that reduced fiber strength resulting from the Mechanical Treatment of kraft pulp was caused by changes in the fiber wall, rather than by changes in fiber bonding or fiber deformations. This study focuses on the nature of the changes in the fiber wall (pore structure) after Mechanical Treatment. The fiber wall structures of Mechanically-treated and untreated fibers were studied in detail using different analytical techniques in order to gain information on the changes in the fiber wall pore structure and fiber wall swelling. The damage reduced the ability of the fiber wall to hold water, changes that could be measured using water retention determinations and swelling experiments with alkaline iron chloride-sodium tartrate (EWNN, Eisen ( I I I ) Weisensaure Natrium-Komplex freier Natronlauge) solution. Fiber wall accessibility was studied by solute exclusion (fiber saturation point, FSP), thermoposimetry and Simons' staining. The strength loss induced by Mechanical Treatment was concluded to be due to ultra-structural changes in the fiber wall, micropore closure and macropore opening, which also led to changes in water holding ability. A possible reason for the decreased strength of the Mechanically-treated fibers could be that there were fewer bonding sites between the parts of the cell wall due to macro pore opening, in contrast to the cell walls of untreated fibers.
-
The effect of Mechanical Treatment on softwood kraft pulp fibers. Fiber surface layer
2004Co-Authors: Olli Joutsimo, Leif RobertsenAbstract:Our earlier studies have shown that Mechanical Treatment of kraft pulp lead to severe strength losses which could not be completely explained by fiber deformations such as curl, kink or dislocations. In this study the effects of Mechanical Treatment of kraft pulp fibers at high temperature on the surface layers were investigated using several techniques. Neither the fiber surface fibrillation nor fines generation could explain the good z-directional bonding of the Mechanically-treated fibers. The contact ratio measurement indicated that the bonding area of the treated pulp was lower, due to the higher curl of the mixed pulp fibers. Atomic Force Microscopy and immunolabelling studies showed that the surface elasticity of the Mechanically-treated pulp was more variable and there was more fiber surface accessible. Mechanical Treatment also affected the water retention value of the fibers. Differences in water retention value could not be explained by differences in fiber charge. Solid state NMR-studies showed no differences in the polymorphs of the cellulose, which could explain the strength losses.
-
The effect of Mechanical Treatment on softwood kraft pulp fibers. Pulp and fiber properties
2004Co-Authors: Olli Joutsimo, Leif RobertsenAbstract:In this study the effects of Mechanical Treatment of kraft pulp fibers, at different temperatures, on pulp and pulp strength properties were investigated. The beating demand increased while the tear index and zero-span tensile strength of treated pulps decreased as the Treatment temperature was increased from 100°C to 170°C. The carbohydrate compositions measured as monosaccharides after acid hydrolysis of the pulps were the same. The small differences in fiber deformation of the bleached pulps could not explain the severe strength losses at 170°C. The fracture analysis, together with the results of a fractionation study of treated pulps, indicated that single fiber strength was lost. The results also indicated that the fiber damage resulting from Mechanical Treatment at high temperature under alkaline cooking conditions led not to a reduction in interfiber bonding ability.