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Wyświetlanie 1-9 z 9
Tytuł:
Modeling of Dendritic Structure Evolution During Solidification of Al-Cu Alloy
Autorzy:
Zyska, A.
Boroń, K.
Kordas, P.
Powiązania:
https://bibliotekanauki.pl/articles/382278.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alloy solidification
cellular automata
AlCu alloy
structure modeling
krzepnięcie stopu
automat komórkowy
stop AlCu
modelowanie struktury
Opis:
The paper presents the cellular automaton (CA) model for tracking the development of dendritic structure in non-equilibrium solidification conditions of binary alloy. Thermal, diffusion and surface phenomena have been included in the mathematical description of solidification. The methodology for calculating growth velocity of the liquid-solid interface based on solute balance, considering the distribution of the alloy component in the neighborhood of moving interface has been proposed. The influence of solidification front curvature on the equilibrium temperature was determined by applying the Gibbs Thomson approach. Solute and heat transfer equations were solved using the finite difference method assuming periodic boundary conditions and Newton cooling boundary condition at the edges of the system. The solutal field in the calculation domain was obtained separately for solid and liquid phase. Numerical simulations were carried out for the Al-4 wt.% Cu alloy at two cooling rates 15 K/s and 50 K/s. Microstructure images generated on the basis of calculations were compared with actual structures of castings. It was found that the results of the calculations are agreement in qualitative terms with the results of experimental research. The developed model can reproduce many morphological features of the dendritic structure and in particular: generating dendritic front and primary arms, creating, extension and coarsening of secondary branches, interface inhibition, branch fusion, considering the coupled motion and growth interaction of crystals.
Źródło:
Archives of Foundry Engineering; 2018, 18, 4; 87-92
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modification Mechanism and Growth Process of Al3(Sc, Zr) Particles in As-cast Al-Si-Mg-Cu-Zr-Sc Alloy
Autorzy:
Li, Y.
Du, X.
Fu, J.
Zhang, Y.
Zhang, Z.
Zhou, S.
Wu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/382672.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
Al3(Sc, Zr)
three-dimensional morphology
eutectic growth
krzepnięcie stopu
morfologia trójwymiarowa
wzrost eutektyczny
Opis:
In this study, the modification mechanism and growth process of Al3(Sc, Zr) particles in as-cast Al-Si-Mg-Cu based alloy with addition of Sc and Zr were systematically investigated. It was found that 0.57 wt-%Sc addition caused a significant refinement in the average grain size of the investigated alloy, which brought about a remarkable transformation in as-cast microstructure, from thick dendritic shape to fine equiaxed structure. A large amount of primary Al3(Sc, Zr) particles with the dimension of around 5-6 μm were also observed within the equiaxed grain. Due to the identical orientation and similar crystal structure between primary Al3(Sc, Zr) particles and α-Al matrix, the primary particles always served as heterogeneous nucleus for the α-Al matrix. In addition, these cusped cubic primary Al3(Sc, Zr) particles showed triangle, star, rhomboid morphologies are generated from sectioning the particle in (111), (100) and (110) planes, respectively. Particularly, the typical eutectic structure which contained odd number-layer (Al3(Sc, Zr)+α-Al+ ... +Al3(Sc, Zr)) was observed within the investigated particles.
Źródło:
Archives of Foundry Engineering; 2018, 18, 2; 51-56
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problem of the moving boundary in continuous casting solved by the analytic-numerical method
Autorzy:
Grzymkowski, R.
Pleszczyński, M.
Hetmaniok, E.
Powiązania:
https://bibliotekanauki.pl/articles/383233.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
information technology
foundry industry
solidification process
numerical techniques
moving boundary problem
technologia informacyjna
przemysł odlewniczy
krzepnięcie stopu
technika numeryczna
problem brzegowy
Opis:
Mathematical modeling of thermal processes combined with the reversible phase transitions of type: solid phase – liquid phase leads to formulation of the parabolic or elliptic moving boundary problem. Solution of such defined problem requires, most often, to use some sophisticated numerical techniques and far advanced mathematical tools. The paper presents an analytic-numerical method, especially attractive from the engineer’s point of view, applied for finding the approximate solutions of the selected class of problems which can be reduced to the one-phase solidification problem of a plate with the unknown a priori, varying in time boundary of the region in which the solution is sought. Proposed method is based on the known formalism of initial expansion of a sought function, describing the field of temperature, into the power series, some coefficients of which are determined with the aid of boundary conditions, and on the approximation of a function defining the freezing front location with the broken line, parameters of which are determined numerically. The method represents a combination of the analytical and numerical techniques and seems to be an effective and relatively easy in using tool for solving problems of considered kind.
Źródło:
Archives of Foundry Engineering; 2013, 13, 1; 33-38
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of influence of the mold material on the distribution of shrinkage cavities
Autorzy:
Dyja, R.
Powiązania:
https://bibliotekanauki.pl/articles/379945.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
information technology
foundry industry
casting defect
macroshrinkage
solidification process
finite element method
technologia informacyjna
przemysł odlewniczy
wada odlewu
krzepnięcie stopu
metoda elementów skończonych
Opis:
Production of castings, like any other field of technology is aimed at providing high-quality product, free from defects. One of the main causes of defects in castings is the phenomenon of shrinkage of the casting. This phenomenon causes the formation of shrinkage cavities and porosity in the casting. The major preventive measure is supplementing a shortage of liquid metal. For supplement to be effective, it is necessary to use risers in proper shapes. Usually, the risers are selected on the basis of determination the place of formation of hot-spots in the castings. Although in these places the shrinkage defects are most likely to occur, shape and size of these defects are also affected by other factors. The article describes the original program setting out the shape and location of possible cavities in the casting. In the program is also taken into account the effect of temperature on the change in volume of liquid metal and the resultant differences in the shape and size of formed shrinkage cavities. The aim of the article is to describe the influence that have material properties of the mold on the simulation results.
Źródło:
Archives of Foundry Engineering; 2013, 13, 1; 15-18
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of Casting Technologies for Al-Si-Cu Plate Casting
Autorzy:
Cupido, L. H.
Żak, P. L.
Powiązania:
https://bibliotekanauki.pl/articles/379873.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
information technology
foundry industry
aluminium alloy
oxide film
casting simulation
krzepnięcie stopu
technologia informatyczna
przemysł odlewniczy
stop aluminium
warstwa tlenkowa
symulacja odlewania
Opis:
During the casting of aluminium alloys, the susceptibility to form oxide films is high, due to the turbulent flow of the melt and constant exposure of new surface area. This have impact on the properties of the material and the service life of the casting components. Also, hydrogen solubility in the solid state are very low, which ends up being rejected and causing porosity. After pouring, when solidification occurs, another phenomenon arise called shrinkage. This require excess molten metal to be fed during this phase change to eliminate or reduce the effect of volumetric changes. Filling and feeding during aluminium casting is therefore of paramount importance, and careful steps needs to be undertaken to reduce possible defects in the castings. The objective is to apply studied literature guides and rules and simulate the casting process of aluminium alloys, and understand the how certain defects are occurring during this process. This is a preliminary study towards the understanding of the “macro evolution” of Al-Si-Cu alloy during solidification, which will be the bases for the study of microsegregation of the specified alloy.
Źródło:
Archives of Foundry Engineering; 2013, 13, 3 spec.; 11-14
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Mesh Quality on the Numerical Solution of the Solidification of Pure Metal
Autorzy:
Skrzypczak, T.
Węgrzyn-Skrzypczak, E.
Powiązania:
https://bibliotekanauki.pl/articles/381672.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
information technology
foundry industry
pure metal
Stefan problem
finite element method
krzepnięcie stopu
technologia informatyczna
przemysł odlewniczy
metal czysty
zagadnienie Stefana
metoda elementów skończonych
Opis:
The paper presents a method of mathematical and numerical modelling of directional solidification process of pure metal in the two-dimensional region. In this case, the thermal conditions associated with the process favours the occurrence of sharp solidification front. The mathematical description of the process is based on the Stefan formulation with appropriate continuity conditions on the solid-liquid interface. The numerical model is based on the finite element method (FEM). The calculations were made on a fixed mesh with diffused solidification front to avoid the difficulties associated with the discontinuity. Temporary position of the interface was calculated with the use of the level set method (LSM). Effect of the quality of the spatial discretization on the accuracy of numerical solution was investigated. Obtained results of the temporary front position were compared with the analytical solution. The correlation between the quality of the spatial discretization and the accuracy of the results was observed. Methods used in the work had significant impact on the computation time and helped avoid the explicit consideration of discontinuity of heat flux on the front.
Źródło:
Archives of Foundry Engineering; 2013, 13, 2 spec.; 89-92
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of phase-change boundary position in continuous casting
Autorzy:
Ivanova, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/380559.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
information technology
foundry industry
mathematical modeling
temperature distribution
Stefan condition
phase change boundary
continuous casting
krzepnięcie stopu
technologia informacyjna
przemysł odlewniczy
modelowanie matematyczne
rozkład temperatury
warunek Stefana
granica międzyfazowa
odlewanie ciągłe
Opis:
The problem of determination of the phase-change boundary position at the mathematical modeling of continuous ingot temperature field is considered. The description of the heat transfer process takes into account the dependence of the thermal physical characteristics on the temperature, so that the mathematical model is based on the nonlinear partial differential equations. The boundary position between liquid and solid phase is given by the temperatures equality condition and the Stefan condition for the two-dimensional case. The new method of calculation of the phase-change boundary position is proposed. This method based on the finite-differences with using explicit schemes and on the iteration method of solving of non-linear system equations. The proposed method of calculation is many times faster than the real time. So that it amenable to be used for model predictive control of continuous semifinished product solidification.
Źródło:
Archives of Foundry Engineering; 2013, 13, 4; 57-62
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of Metal Quality and Porosity Formation in Low Pressure Die Casting of A356: Experimental Observations
Autorzy:
Gursoy, O.
Nordmak, A.
Syversten, F.
Colak, M.
Tur, K.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/1837851.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die casting
alloy A356
solidification
LPDC
aluminium
quality of alloy
bifilm
porosity
odlewanie ciśnieniowe
stop A356
krzepnięcie
właściwości stopu
porowatość
Opis:
Porosity is one of the major problems in casting operations and there are several discussions in the literature about the porosity formation in aluminum castings. Bifilms are the defects that are introduced into the melt by turbulence. They can be detected with reduced pressure test and presented numerically by measuring bifilm index. The measure of bifilm index is the sum of total oxide length given in millimeters from the cross-section of reduced pressure test sample solidified under 0.01 MPa. In this work, low pressure die casting (LPDC) unit was built in an attempt to enhance the producibility rate. The unit consists of a pump housing that was placed inside the melt in the melting furnace where the pressure was applied instead of the whole melt surface. It was observed that the melt quality of A356 alloy was deteriorated over time which had led to higher porosity. This was attributed to the increased oxide thickness of the bifilm by the consumption of air in between the folded oxides. A relationship was found between bifilm index and pore formation.
Źródło:
Archives of Foundry Engineering; 2021, 21, 1; 5-10
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of Metal Quality and Porosity Formation in Low Pressure Die Casting of A356: Experimental Observations
Autorzy:
Gursoy, O.
Nordmak, A.
Syversten, F.
Colak, M.
Tur, K.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/1837813.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die casting
alloy A356
solidification
LPDC
aluminium
quality of alloy
bifilm
porosity
odlewanie ciśnieniowe
stop A356
krzepnięcie
właściwości stopu
porowatość
Opis:
Porosity is one of the major problems in casting operations and there are several discussions in the literature about the porosity formation in aluminum castings. Bifilms are the defects that are introduced into the melt by turbulence. They can be detected with reduced pressure test and presented numerically by measuring bifilm index. The measure of bifilm index is the sum of total oxide length given in millimeters from the cross-section of reduced pressure test sample solidified under 0.01 MPa. In this work, low pressure die casting (LPDC) unit was built in an attempt to enhance the producibility rate. The unit consists of a pump housing that was placed inside the melt in the melting furnace where the pressure was applied instead of the whole melt surface. It was observed that the melt quality of A356 alloy was deteriorated over time which had led to higher porosity. This was attributed to the increased oxide thickness of the bifilm by the consumption of air in between the folded oxides. A relationship was found between bifilm index and pore formation.
Źródło:
Archives of Foundry Engineering; 2021, 21, 1; 5-10
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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