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1
Content available Modelling the composition of carbides in nickel-based superalloys of directional crystallization
Glotka O. A.
Journal of Achievements in Materials and Manufacturing Engineering
|
2020
|
Vol. 102, nr 1
5--15
EN
Purpose: The specifics of the influence of alloying elements on the chemical composition of various types of carbides, their topology and morphology for a multicomponent system of the type Ni-5Cr-9Co-6Al-1Ti-11.7W-1.1Mo-1.6Nb-0.15C using the calculation method CALPHAD. It is shown that the obtained dependences closely correlate with thermodynamic processes occurring in the system. Design/methodology/approach: This work presents the results of studies of the distribution of chemical elements in the composition of carbides, depending on their content in the system. Findings: It was found that the influence of alloying elements on the composition of carbides is complex and is described by complex. Research limitations/implications: An essential problem is the prediction of the structure and properties of heat-resistant alloys without or with a minimum number of experiments. Practical implications: The obtained dependences can be used both for designing new heat-resistant alloys and for improving the compositions of industrial alloys. Originality/value: The value of this work is that the obtained dependences of the influence of alloying elements on the dissolution (precipitation) temperatures and the distribution of elements in carbides in the alloy of the Ni-5Cr-9Co-6Al-1Ti-11.7W-1.1Mo-1.6Nb-0.15C.
2
Content available Leading Phase in the Directionally Solidifying Fe – 4.25%C Eutectic Alloy
Trepczyńska-Łent M.
Archives of Foundry Engineering
|
2019
|
iss. 4
113--116
EN
In order to determine the leading phase of the Fe - 4.25% C eutectic alloy, the method of directional crystallization, which allows to study the character of the solid / liquid growth front, was used. Examined eutectic was directionally solidified with a constant temperature gradient of G = 33,5 K/mm and growth rate of v = 125 μm/s (450 mm/h). The Bridgman technique was used for the solidification process. The sample was grown by pulling it downwards up to 30 mm in length. The alloy quenched by rapid pulling down into the Ga-In-Sn liquid metal. The sample was examined on the longitudinal section using a light microscope and scanning electron microscope. The shape of the solid/liquid interface and particularly the leading phase protrusion were revealed. The formation of the concave – convex interface has been identified in the quasi-regular eutectic growth arrested by quenching. The cementite phase was determined to be a leading phase. The total protrusion d is marked in the adequate figure.
3
Content available Assessment of Mechanism of Pore Formation in Directionally Solidified A356 Alloy
Uludag M., Dispinar D.
Archives of Foundry Engineering
|
2017
|
Vol. 17, iss. 1
157--162
EN
It is well-known that the better the control of the liquid aluminium allows obtaining of better properties. One of the most important defects that is held responsible for lower properties has been the presence of porosity. Porosity has always been associated with the amount of dissolved hydrogen in the liquid. However, it was shown that hydrogen was not the major source but only a contributor the porosity. The most important defect that causes porosity is the presence of bifilms. These defects are surface entrained mainly due to turbulence and uncontrolled melt transfer. In this work, a cylindrical mould was designed (Ø30 x 300 mm) both from sand and die. Moulds were produced both from sand and die. Water cooled copper chill was placed at the bottom of the mould in order to generate a directional solidification. After the melt was prepared, prior to casting of the DC cast samples, reduced pressure test sample was taken to measure the melt quality (i.e. bifilm index). The cast parts were then sectioned into regions and longitudinal and transverse areas were investigated metallographically. Pore size, shape and distribution was measured by image analysis. The formation of porosity was evaluated by means of bifilm content, size and distribution in A356 alloy.
4
Content available XRD and EBSD Measurements of Directional Solidification Fe-C Eutectic Alloy
Trepczyńska-Łent M.
Archives of Foundry Engineering
|
2016
|
Vol. 16, iss. 4
169--174
EN
In a vacuum Bridgman-type furnace, under an argon atmosphere, directionally solidified sample of Fe-C alloy was produced. The pulling rate was v = 83 μm/s (300 mm/h) and constant temperature gradient G = 33,5 K/mm. The microstructure of the sample was examined on the longitudinal section using an Optical Microscope and Scanning Electron Microscope. The X-ray diffraction and electron backscatter diffraction technique (EBSD) have been used for the crystallographic analysis of carbide particles in carbide eutectic. The X-ray diffraction was made parallel and perpendicular to the axis of the goniometer. The EBSD shows the existence of iron carbide Fe3C with orthorhombic and hexagonal structure. Rapid solidification may cause a deformation of the lattice plane which is indicated by different values of the lattice parameters. Such deformation could also be the result of directional solidification. Not all of the peaks in X–ray diffractograms were identified. They may come from other iron carbides. These unrecognized peaks may also be a result of the residual impurity of alloy.
5
Content available Solidification Front of Oriented Ledeburite
Trepczyńska-Łent M., Olejnik E.
Archives of Foundry Engineering
|
2016
|
Vol. 16, iss. 1
124--130
EN
Directional solidification of the Fe - 4,3 wt % C alloy was performed with the pulling rate equal to v=83 μm/s. Sample was frozen during solidification to reveal the shape of the solid/liquid interface. Structures eutectic pyramid and spherolitic eutectic were observed. The solidification front of ledeburite eutectic was revealed. The leading phase was identified and defined.
6
Content available X-ray Diffraction Study of Directional Solidification Ledeburite
Trepczyńska-Łent M., Szykowny T.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 3
71--76
EN
Directionally solidified sample of Fe-Fe3C eutectic alloy were produced under an argon atmosphere in a vacuum Bridgman-type furnace to study the eutectic growth with v = 167 μm/s pulling rate and constant temperature gradient G = 33.5 K/mm. Since how the growth texture of eutectic cementite is related to its growth morphology remains unclear, the current study aims to examine this relationship. The technique such as X-ray diffraction, have been used for the crystallographic analysis of carbide particles in white cast irons.
7
Content available Thermodynamic Assessment of Mushy Zone in Directional Solidification
Mikołajczak P., Ratke L.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 4
101--109
EN
Solidification of AlSiFe alloys was studied using a directional solidification facility and the CALPHAD technique was applied to calculate phase diagrams and to predict occurring phases. The specimens solidified by electromagnetic stirring showed segregation across, and the measured chemical compositions were transferred into phase diagrams. The ternary phase diagrams presented different solidification paths caused by segregation in each selected specimen. The property diagrams showed modification in the sequence and precipitation temperature of the phases. It is proposed in the study to use thermodynamic calculations with Thermo-Calc which enables us to visualize the mushy zone in directional solidification. 2D maps based on property diagrams show a mushy zone with a liquid channel in the AlSi7Fe1.0 specimen center, where significant mass fraction (33%) of β-Al5FeSi phases may precipitate before α-Al dendrites form. Otherwise liquid channel occurred almost empty of β in AlSi7Fe0.5 specimen and completely without β in AlSi9Fe0.2. The property diagrams revealed also possible formation of α–Al8Fe2Si phases.
8
Content available Anisotropic in Situ Metal Matrix Composite Reinforced with VC Carbide Fibres
Kawalec M., Górny M., Sikora G.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 1
21--24
EN
A eutectic reaction is a basic liquid-solid transformation, which can be used in the fabrication of high-strength in situ composites. In this study an attempt was made to ensure directional solidification of Fe-C-V alloy with hypereutectic microstructure. In this alloy, the crystallisation of regular fibrous eutectic and primary carbides with the shape of non-faceted dendrites takes place. According to the data given in technical literature, this type of eutectic is suitable for the fabrication of in-situ composites, owing to the fact that a flat solidification front is formed accompanied by the presence of two phases, where one of the phases can crystallise in the form of elongated fibres. In the present study an attempt was also made to produce directionally solidifying vanadium eutectic using an apparatus with a very high temperature gradient amounting to 380 W/cm at a rate of 3 mm/h. Alloy microstructure was examined in both the initial state and after directional solidification. It was demonstrated that the resulting microstructure is of a non-homogeneous character, and the process of directional solidification leads to an oriented arrangement of both the eutectic fibres and primary carbides.
9
Content available Effect of Contact Gap in Directional Solidification of AlSiFe Alloys
Mikołajczak P., Ratke L.
Archives of Foundry Engineering
|
2014
|
Vol. 14, iss. 3 spec.
41--44
EN
One of the methods to study solidification of alloys and metals is directional solidification. In the paper the effect of the contact gap between the analyzed specimen and the bottom heater was analysed. The occurring contact gap caused the increase in planned solidification velocity. For the facility calibration the methodology with M coefficient was applied. The experiments revealed efficient values of M and allowed to conduct efficiently the directional solidification of AlSiFe alloys in wide range of growth rates. The effect of the contact gap seems to be random phenomena and most difficult factor influencing precisely planned directional solidification.
10
Content available Directional Solidification of AlSi Alloys with Fe Intermetallic Phases
Mikołajczak P., Ratke L.
Archives of Foundry Engineering
|
2014
|
Vol. 14, iss. 1
75--78
EN
Directional solidification technique is an important research instrument to study solidification of metals and alloys. In the paper the model [6,7,8] of directional solidification in special Artemis-3 facility was presented. The current work aimed to propose the ease and efficient way in calibrating the facility. The introduced M coefficient allowed effective calibration and implementation of defined thermal conditions. The specimens of AlSi alloys with Fe-rich intermetallics and especially deleterious β-Al5FeSi were processed by controlled solidification velocity, temperature gradient and cooling rate.
11
Content available Directional solidification of ledeburite
Trepczyńska-Łent M.
Archives of Foundry Engineering
|
2013
|
Vol. 13, iss. 3
101--106
EN
Directional solidification of ledeburite was realised out using a Bridgman’s device. The growth rate for movement sample v=83.3 μm/s was used. In one sample the solidification front was freezing. The value of temperature gradient in liquid at the solidification front was determined. Interfacial distance λ on the samples was measured with NIS-Elements application for image analysis.
12
Content available Nowy sposób wytwarzania odlewów precyzyjnych ze stopu miedzi w formach ceramicznych
Czekaj E., Karwiński A., Pączek Z., Pysz S.
Archives of Foundry Engineering
|
2012
|
Vol. 12, iss. 2s
9--16
PL
W publikacji zaprezentowano wyniki badań odlewów wytwarzanych ze stopu miedzi (brązu aluminiowego, typu BA1044) według opracowanej w Instytucie Odlewnictwa w Krakowie technologii wykonywania odlewów precyzyjnych przy zastosowaniu kierunkowego krzepnięcia [9]. Wstępnie pokazano zasadność nowoopracowanego w Polsce sposobu wytwarzania skomplikowanych konstrukcyjnie, a zarazem wysokojakościowych (z uwagi na właściwości użytkowe) części maszyn, urządzeń i pojazdów ze stopów miedzi. Proponowane rozwiązanie jest innowacją nie tylko w skali kraju (Polski), ale również o zasięgu międzynarodowym.
13
Content available remote Mathematical and numerical model of directional solidification including initial and terminal transients of the process
Kapturkiewicz W., Burbelko A. A., Fraś E.
Archives of Foundry Engineering
|
2008
|
Vol. 8, iss. 4
65-70
EN
The, developed in this study, simple model and numerical solution of diffusion growth of the solid phase under the conditions of directional solidification allow for the effect of constituent diffusion in both liquid and solid phase and assume the process run in which (like in reality) the preset parameter is the velocity of sample (pulling velocity) at a preset temperature gradient. The solid/liquid interface velocity is not the process parameter (like it is in numerous other solutions proposed so far) but a function of this process. The effect of convection outside the diffusion layer has been included in mass balance under the assumption that in the zone of convection the mixing is complete. The above assumptions enabled solving the kinetics of growth of the solid phase (along with the diffusion field in solid and liquid phase) under the conditions of diffusion well reflecting the process run starting with the initial transient state, going through the steady state period in central part of the casting, and ending in a terminal transient state. In the numerical solution obtained by the finite difference method with variable grid dimensions, the error of the mass control balance over the whole process range was 1- 2%.
14
Content available remote Wykorzystanie automatów komórkowych do symulacji krzepnięcia kierunkowego
Marek M.
Archiwum Odlewnictwa
|
2004
|
R. 4, nr 14
285-290
PL
W artykule przedstawiono wyniki zastosowania modelu komórkowego do symulowania przebiegu krystalizacji kierunkowej stopu dwuskładnikowego. W pierwszej części opisano podstawowe założenia modelu, zaś w drugiej - przykładowe rezultaty uzyskane za jego pomocą.
EN
Results of application of cellular automaton model to simulation of directional solidification of binary alloy are shown in this paper. In the first part the model itself is described, in the second one - some example results obtained with the use of the model.
15
Content available remote Badania frontu krystalizacji dwuskładnikowych stopów Al - Si w kanałach metalowych form odlewniczych
Mutwil J., Janowski R., Michalski M.
Archiwum Odlewnictwa
|
2002
|
R. 2, nr 6
141-148
PL
Dla aluminium i jego stopów z krzemem przedstawiono skaningowe obrazy frontu krystalizacji strugi krzepnącej w kanale formy metalowej.
EN
For aluminum and aluminum-silicon alloys flowing and solidifying in metal mould channel the SEM-micrographs of crystallization interface have been presented.
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