scholarly journals The Analysis of Temporary Temperature Field and Phase Transformations in One-Side Butt-Welded Steel Flats

10.5772/63994 ◽  
2016 ◽  
Author(s):  
Jerzy Winczek
Keyword(s):  
Temperature Field ◽  
Phase Transformations ◽  
Welded Steel

Mathematical Modeling of Thermal Association in a Porous Medium with a Capillary Effect in Anisotropic Composite Materials

2018 ◽  
Vol 771 ◽  
pp. 136-143
Author(s):  
Ekaterina Kuznetsova ◽  
Lev Rabinskiy
Keyword(s):  
Temperature Field ◽  
Composite Materials ◽  
Phase Transformations ◽  
Heat Conduction Problem ◽  
Pressure Ratio ◽  
Outer Boundary ◽  
The Body ◽  
Movable Boundary ◽  
Continuity Equations ◽  
Pyrolysis Gases

Authors developed a mathematical model of heat and mass transfer in multidimensional bodies made of composite materials, taking into account porosity and capillarity. Continuity equations for pyrolysis gases were taken for the research: the pressure ratio at the outer boundary of the body. Based on the nonstationary heat conduction problem, under conditions of high-intensity heat transfer at the boundaries of bodies, taking into account the laws of decomposition and non-linear filtration of pyrolysis gases through a porous residue, the time distribution of the movable boundary of phase transformations and the distribution of the temperature field along the variable coordinate at different instants of time are obtained. It was found that, although the thermal load at the outer boundaries is symmetric with respect to the symmetry axis, there is an obvious asymmetry in the temperature field and the movable boundary of the phase transformations.

scholarly journals Numerical Modelling Of Thermal And Structural Phenomena In Yb:YAG Laser Butt-Welded Steel Elements

2015 ◽  
Vol 60 (2) ◽  
pp. 821-828 ◽  
Author(s):  
M. Kubiak ◽  
W. Piekarska ◽  
S. Stano ◽  
Z. Saternus
Keyword(s):  
Phase Transformations ◽  
Numerical Models ◽  
Welding Process ◽  
Source Model ◽  
Welded Steel ◽  
Heating And Cooling ◽  
Real Distribution ◽  
Classical Models ◽  
Volume Method ◽  
Cct Diagrams

AbstractThe numerical model of thermal and structural phenomena is developed for the analysis of Yb:YAG laser welding process with the motion of the liquid material in the welding pool taken into account. Temperature field and melted material velocity field in the fusion zone are obtained from the numerical solution of continuum mechanics equations using Chorin projection method and finite volume method. Phase transformations in solid state are analyzed during heating and cooling using classical models of the kinetics of phase transformations as well as CTA and CCT diagrams for welded steel. The interpolated heat source model is developed in order to reliably reflect the real distribution of Yb:YAG laser power obtained by experimental research on the laser beam profile.On the basis of developed numerical models the geometry of the weld and heat affected zone are predicted as well as the structural composition of the joint.

scholarly journals Numerical simulations of progressive hardening by using ABAQUS FEA software

2018 ◽  
Vol 157 ◽  
pp. 02007 ◽  
Author(s):  
Tomasz Domański ◽  
Wiesława Piekarska ◽  
Marcin Kubiak ◽  
Zbigniew Saternus ◽  
Dorota Goszczyńska-Króliszewska
Keyword(s):  
Temperature Field ◽  
Solid State ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Phase Transformations ◽  
Continuous Heating ◽  
Thermal Fields ◽  
Kinetics Of ◽  
Fortran Programming Language ◽  
Structural Strain

The paper concerns numerical simulations of progressive hardening include phase transformations in solid state of steel. Abaqus FEA software is used for numerical analysis of temperature field and phase transformations. Numerical subroutines, written in fortran programming language are used in computer simulations where models of the distribution of movable heat source, kinetics of phase transformations in solid state as well as thermal and structural strain are implemented. Model for evaluation of fractions of phases and their kinetics is based on continuous heating diagram and continuous cooling diagram. The numerical analysis of thermal fields, phase fractions and strain associated progressive hardening of elements made of steel were done.

Characteristics and Application of Temperature-Field Emitters

1975 ◽  
Vol 33 ◽  
pp. 144-145
Author(s):  
N. Tamura ◽  
T. Goto ◽  
Y. Harada
Keyword(s):  
Temperature Field ◽  
Electron Microscope ◽  
Field Emission ◽  
Resolving Power ◽  
High Brightness ◽  
Field Emitters ◽  
Emission Electron ◽  
Sufficient Stability ◽  
Scanning Electron ◽  
Illuminating System

On account of its high brightness, the field emission electron source has the advantage that it provides the conventional electron microscope with highly coherent illuminating system and that it directly improves the, resolving power of the scanning electron microscope. The present authors have reported some results obtained with a 100 kV field emission electron microscope.It has been proven, furthermore, that the tungsten emitter as a temperature field emission source can be utilized with a sufficient stability under a modest vacuum of 10-8 ~ 10-9 Torr. The present paper is concerned with an extension of our study on the characteristics of the temperature field emitters.

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

1993 ◽  
Vol 51 ◽  
pp. 842-843
Author(s):  
K. Barmak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformations ◽  
Analytical Electron Microscopy ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
Absolute Concentration ◽  
Analytical Electron ◽  
Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

Multiple-fracturing and viewing of the same frozen sample at different depths using a low temperature FESEM

1996 ◽  
Vol 54 ◽  
pp. 820-821
Author(s):  
M.V. Parthasarathy ◽  
C. Daugherty
Keyword(s):  
Temperature Field ◽  
Low Temperature ◽  
Field Emission ◽  
Multiple Fracture ◽  
Precise Control ◽  
Cold Stage ◽  
Different Depths ◽  
Transfer Device

The versatility of Low Temperature Field Emission SEM (LTFESEM) for viewing frozen-hydrated biological specimens, and the high resolutions that can be obtained with such instruments have been well documented. Studies done with LTFESEM have been usually limited to the viewing of small organisms, organs, cells, and organelles, or viewing such specimens after fracturing them.We use a Hitachi 4500 FESEM equipped with a recently developed BAL-TEC SCE 020 cryopreparation/transfer device for our LTFESEM studies. The SCE 020 is similar in design to the older SCU 020 except that instead of having a dedicated stage, the SCE 020 has a detachable cold stage that mounts on to the FESEM stage when needed. Since the SCE 020 has a precisely controlled lock manipulator for transferring the specimen table from the cryopreparation chamber to the cold stage in the FESEM, and also has a motor driven microtome for precise control of specimen fracture, we have explored the feasibility of using the LTFESEM for multiple-fracture studies of the same sample.

A Transmission Electron Microscopical Investigation of Phase Transformations in TiNi

1980 ◽  
Vol 38 ◽  
pp. 340-341
Author(s):  
P. Moine ◽  
G. M. Michal ◽  
R. Sinclair
Keyword(s):  
Electron Microscopy ◽  
Phase Transformations ◽  
Applied Stress ◽  
Structural Changes ◽  
Microscopical Investigation ◽  
Temperature Range ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Diffraction Effects ◽  
Microscopy Images

Premartensitic effects in near equiatomic TiNi have been pointed out by several authors(1-5). These include anomalous contrast in electron microscopy images (mottling, striations, etc. ),diffraction effects(diffuse streaks, extra reflections, etc.), a resistivity peak above Ms (temperature at which a perceptible amount of martensite is formed without applied stress). However the structural changes occuring in this temperature range are not well understood. The purpose of this study is to clarify these phenomena.

Sign in / Sign up

Export Citation Format

Share Document