V. T. Witusiewicz

V. T. Witusiewicz
RWTH Aachen University · ACCESS

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131
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Publications

Publications (131)
Article
Full-text available
We review recent in situ solidification experiments using nonfaceted model transparent alloys in science-in-microgravity facilities onboard the International Space Station (ISS), namely the Transparent Alloys (TA) apparatus and the Directional Solidification Insert of the DEvice for the study of Critical Liquids and Crystallization (DECLIC-DSI). Th...
Article
At a stationary temperature gradient, the grain boundaries comprising residual melt can migrate. Their migration is governed by liquid diffusion and, in multiphase materials, depends highly on the phases present. Therefore, this phenomenon can be used for phase identification if data on metastable extensions of the corresponding phase diagram are a...
Article
The present paper reports on the thermodynamic modelling of the complete ternary Fe–Ni–Si system based on key experimental results and information reported in literature. The key experiments were performed to verify phases and phase fractions in selected ternary Fe–Ni–Si alloys using samples in the as-cast state as well as annealed samples. Chemica...
Article
We present results from a combined experimental and numerical approach to estimate the impact of thermodiffusion in the liquid phase of the binary system neopentylglycol-(D)camphor (NPG-DC) during the pre-solidification holding period of experiments on the International Space Station (ISS) in reduced gravity conditions. The Soret coefficient ST, di...
Article
Site preference and thermodynamic properties of the ternary Laves phase Ti(Fe1 –xAlx)2 with MgZn2-type have been studied employing Rietveld refinement of X-ray and neutron powder diffraction data, X-ray single crystal data, and isoperibolic drop calorimetry techniques. A detailed relation between lattice parameters of Ti(Fe1– xAlx)2 and the Al cont...
Article
Full-text available
We present the first observations of a large-scale coexistence between rod-like and lamellar eutectic growth patterns during directional solidification of a eutectic alloy. In situ experiments with real-time optical monitoring were carried out under microgravity onboard the International Space Station (ISS). We used the transparent succinonitrile-d...
Article
Full-text available
Time- and temperature-resolved phase formation in the equiatomic NbTiVZr refractory high-entropy alloy has been studied in situ using high-energy synchrotron X-ray diffraction and high-speed video imaging during non-equilibrium solidification. Phase formation is shown to be dependent on the solidification conditions. When the melt is undercooled ov...
Preprint
Time- and temperature-resolved phase formation in the equiatomic NbTiVZr refractory high-entropy alloy has been studied in situ using high-energy synchrotron X-ray diffraction and high-speed video imaging during non-equilibrium solidification. Phase formation upon solidification is shown to be dependent on the processing conditions. When the melt i...
Article
Interaction of melt flow with solidification microstructures is of fundamental interest and technical relevance due to its effect on the selection of characteristic microstructural features and length scales. Here, we report on in-situ optical observation of both melt flow at the solidification front and microstructural evolution in polycrystalline...
Article
Full-text available
The solidification behavior of the CoCrFeNi high-entropy alloy and the ternary CrFeNi and CoCrNi medium-entropy suballoys has been studied in situ using high-temporal-resolution video and synchrotron X-ray diffraction on electromagnetically levitated samples. In all alloys, the formation of a primary metastable bcc phase was observed if the melt wa...
Article
In the present paper, the complete ternary B–Fe–Mo system is thermodynamically re-modelled based on our own experimental results and novel information reported in literature. A few key experiments were performed with ternary B–Fe–Mo alloys in order to clarify the morphology and stability of the MoxFe3-xB phase and measure temperatures of invariant...
Article
In the present work are reported ground-reference results from a series of transient solidification experiments with the organic eutectic alloys SCN-23.6 DC (wt.%) and SCN-24.2DC-0.5NPG (wt.%), which have been performed in preparation of microgravity experiments using a new multi-user facility called Transparent Alloys or DIRSOL. In 1g lab conditio...
Article
Arc-melted Ti100–xMo2Alx alloys (where x is 44, 46, 48, and 50 at.% Al) that were produced from pure components were examined by X-ray diffraction and scanning electron microscopy with electron microprobe analysis (SEM/EDX). The melting points and solid-phase transformations were studied by differential thermal analysis (DTA) and the mechanical pro...
Article
Full-text available
The alloy system Al-Cr-Fe-Ni provides means for developing novel duplex materials composed of face-centered cubic (FCC) and body-centered cubic (BCC) phases with nearly equal volume fraction. We performed an alloy development study starting from the medium entropy alloy AlCrFe 2 Ni 2 and adding small amounts of molybdenum in the following series (a...
Article
Full-text available
In this paper we present and discuss phase equilibria in the quaternary Al–Cr–Fe–Ni and the quinary Al–Co–Cr–Fe–Ni alloy systems based on experimental data from DTA/DSC, SEM/EDS, and SEM/EBSD on as-cast and isothermally annealed samples. These data as well as literature data were used for developing a new Al–Co–Cr–Fe–Ni thermodynamic description by...
Article
In the present paper, the complete ternary B–Fe–Ti system is thermodynamically modelled based on our own experimental results and information reported in literature. Series of key experiments were performed for the binary Fe-B, Fe-Ti and the ternary B-Fe-Ti systems in order to obtain parameters of invariant reactions. For this, 19 alloys were prepa...
Article
Full-text available
We have determined non-isothermal diffusive transport coefficients of a succinonitrile-(d)camphor mixture with a composition of c = 0.239 wt.-frac. (d)camphor at a temperature of 318.2 K, which is close to the eutectic point. The employed experimental techniques are optical beam deflection in a Soret cell and photon correlation spectroscopy. The di...
Conference Paper
We present a high entropy alloy (HEA) from the system Al-Co-Cr-Fe-Ni with small additions of W, Mo, Si and C which was designed to allow for precipitation hardening by annealing in the temperature range from 600 to 900 ° C. The alloy development was supported by thermodynamic computations using ThermoCalc software and the specimens were produced by...
Article
Full-text available
By combining theoretical density functional theory (DFT) and experimental studies, structural and magnetic phase stabilities and electronic structural, elastic, and vibrational properties of the Laves-phase compound NbMn2 have been investigated for the C14, C15, and C36 crystal structures. At low temperatures C14 is the ground-state structure, with...
Article
In the present paper, the complete ternary Al–Mo–Ti system is thermodynamically modelled based on novel experimental information reported in the literature within the past few years. A series of key experiments were performed in addition with selected alloys in order to complement the available data on phase transformation temperatures. Eighteen al...
Article
Controlling the grain size and texture of lamellar TiAl-alloys is essential for well-balanced creep and fatigue properties. Excellent refinement and texture mitigation are achieved in aluminum lean alloys by low boron additions of 0.2 at.%. This amount is sufficient to promote in situ formation of ultrafine borides during the last stages of body ce...
Article
Quaternary as-cast Ti 96–x Nb 2 Cr 2 Al x and Ti 93–x Nb 5 Cr 2 Al x alloys, where x = 44, 46, 48, and 50, melted from pure components (~99.9 wt.%) in a laboratory arc furnace, were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), and differential thermal analysis (DTA). Bending testing and fracture toughness measurements...
Article
The structure and phase transformations in the Ti–Al–C system were studied by X-ray diffraction, differential thermal analysis, and scanning electron microscopy, including energy-dispersive X-ray spectroscopy and electron backscatter diffraction on samples obtained by arc melting and annealing at high temperatures. The ternary system has a cocrysta...
Article
In the present paper, the ternary Al–Cr–Ti and binary constituent Al–Cr systems are thermodynamically re-modelled based on new experimental information reported in the literature within the past few years. Few key experiments were performed with selected ternary alloys in order to complement data on phase equilibria in the composition range of comm...
Article
In the present paper, the constituent binary B-Mo system is re-modelled in order to reproduce genuine homogeneity ranges of the molybdenum borides. Based on this, available descriptions of the constituent B-Ti and Mo-Ti systems as well as new experimental data reported in the literature for the ternary B-Mo-Ti system are used to model the B-Mo-Ti s...
Article
Based on novel experimental data the thermodynamic description of the ternary Al-C-Ti system was subject to optimization using the CALPHAD approach (Thermo-Calc/PARROT). The reaction scheme, the projections of the liquidus and solidus surfaces, as well as a number of isothermal sections and isopleths were calculated using the proposed thermodynamic...
Article
Full-text available
Eutectic alloys from the ternary system Al-Cu-Ag are excellent model alloys for the investigation of coupled eutectic growth, not only because most materials properties are well known but also because the system offers a rich variety of crystal structures and crystal orientation relationships (ORs) being associated to distinct minima of the solid-s...
Article
Full-text available
Phase equilibria and phase transformations in the ternary Al–B–Nb system were investigated by XRD, SEM/WDS and SEM/EDS techniques, DTA, and optic pyrometry. No ternary compound, including the ternary phases reported in literature, was found. It was experimentally measured that the Al–Nb phases ε (NbAl3), σ (prototype σCrFe) and δ (prototype Cr3Si)...
Article
The eutectic spacing (lambda) was investigated in three alloys of succinonitrile-neopentylglycol-(D)camphor-aminomethylpropanediol (SCN-NPG-DC-AMPD) system over a wide range of temperature gradients (G) and growth velocities (V), both in thin <= 5 mu m (two-dimensional (2-D)) samples and in bulk (three-dimensional (3-D)) samples. The compositions w...
Article
Lamellar eutectic growth was investigated in the transparent organic alloy neopentylglycol-(D)camphor of eutectic composition (NPG-45.3 wt% DC) using bulk (3D) and thin (2D) samples. Two types of eutectic grains were observed in the polycrystalline samples, either with lamellae well aligned to the direction of solidification or inclined at an angle...
Article
Alloys from the succinonitrile–(D)camphor (SCN–DC) system are widely used as model alloys for the in situ investigation of solidification using light optical microscopy, but literature on the binary phase diagram is contradictory with respect to the solubility limit of DC in (SCN). Phase equilibria of the system were therefore revisited experimenta...
Article
An experimental method for the in-situ observation of solidification in eutectic metallic alloys growing at moderate temperatures, i.e. 500–600 °C was developed. It is based on unidirectional solidification of thin samples (200 to 700 μm thick) contained in rectangular quartz glass tubes allowing for in-situ observation of growth on the sample surf...
Article
A new experimental method for in-situ observation of microstructure formation in top view during unidirectional solidification of bulk, transparent, organic alloys is presented. This method allows observing growth patterns over an extended interface area with high resolution and minimal optical aberrations. With (D)camphor–neopentylglycol–succinoni...
Article
In the present article, a thermodynamic description of the ternary Al–Fe–Ta system is proposed, being obtained by CALPHAD modelling based on assessed experimental information from literature and our own experimental results. Dedicated experiments were performed to complement literature data on phase equilibria and thermodynamic properties. As-cast...
Article
The partial (Δ\((\Delta \overline H _i )\) and the integral (ΔH) enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys have been determined by high-temperature isoperibolic calorimetry at 1565 ± 5 K. The heat capacity (C p) of liquid Ni26Zr74 has been measured by adiabatic calorimetry (C p=53.5±2.2 J mol−1 K−1 at 1261±15 K). The integral enthalp...
Article
Full-text available
Coupled eutectic growth of Al and Al2Cu was investigated in univariant Al-Cu-Ag alloys during solidification with planar and cellular morphology. Experiments reveal the dynamic selection of small spacings, below the minimum undercooling spacing and show that distinct morphological features pertain to nearly isotropic or anisotropic Al-Al2Cu interfa...
Article
Ternary as-cast Ti55−x Nb x Al45, Ti53−x Nb x Al47, Ti55−x Ta x Al45, and Ti53−x Ta x Al47 alloys, where x = 0, 4, 8, and 12, and Ti45Nb8−x Ta x Al47 and Ti47Nb8−x Ta x Al45 quaternary alloys, where x = 2, 4, and 6, melted in a laboratory arc furnace from pure components (~99.9wt.%) are studied by X-ray diffraction (XRD), scanning and transmission...
Article
Univariant and invariant phase equilibria for systems that display second-order transformations such as chemical and magnetic ordering are arranged consistently aiming to construct complete Scheil’s reaction schemes. For this purpose it is assumed that univariant phase boundaries representing second-order (or higher-order) transformations are nothi...
Article
Phase relations and thermodynamic properties in the binary Fe–Ta system were re-assessed taking into account available and new experimental data. Seven alloys with different chemical composition were prepared. Both, as-cast and annealed samples were analyzed by means of DTA, SEM/EDX and XRD techniques in order to experimentally verify the phase rel...
Article
In the present paper a thermodynamic description of the entire ternary Al–Ta–Ti system is proposed, being obtained by CALPHAD modelling. Dedicated experiments were performed in order to complement literature data on phase equilibria reported mainly for the temperature interval from 1273 to 1723 K. As-cast and annealed samples were investigated by m...
Article
The lamellar alpha(2)(Ti3Al) + gamma(TiAl) microstructure of intermetallic Ti-46Al-8Ta (at %) alloy is thermodynamically unstable and transforms to alpha(2) + gamma + tau type during long-term ageing at 750 degrees C A new ternary tau-phase with B8(2) type structure (space group P6(3)/mmc Pearson symbol hP6) is identified by XRD analysis and its oc...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
In situ observations of phase transformations involving melts are performed using energy-dispersive diffraction of synchrotron X-rays on electromagnetically levitated γ-TiAl alloys containing Nb. The determined primary solidification modes, confirmed by microstructure analysis, delivered new reliable data about the boundary of the α(Ti) solidificat...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
Full-text available
Phase relations in the binary Al–Ta system were re-assessed taking into account recent experimental data. Alloys of different composition were prepared and analyzed by means of DTA, DSC, pyrometry after Pirani–Alterthum, SEM/EDS and SEM/EBSD techniques in order to prove the phase relations in the system. Both, as-cast and annealed samples were inve...
Article
Full-text available
The properties of modern TiAl-based alloys with aluminum contents around 45 at.% critically depend on the as solidified α(Ti) grain structure. Commonly, a rather coarse grain structure is obtained if α(Ti) forms via the peritectic reaction '[Formula: see text]'. Phase-field simulations have been applied to perform a case study of grain structure fo...
Article
Full-text available
Casting of titanium aluminides is an attractive processing route for production of near net shape components: turbocharger wheels, valves and aero-engine components are presently at the heart of casting developments. Among the casting alloys under consideration are a number of niobium rich TiAl based alloys that contain low boron additions for grai...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
Full-text available
The thermodynamic description of the ternary system Al–B–Ti is obtained by modelling the Gibbs energy of all individual phases in the system using the CALPHAD approach. The model parameters have been evaluated using the computer optimization technique PARROT based on the available descriptions of the constituent binary systems Al–B, B–Ti and Al–Ti...
Article
The thermodynamic description of the entire ternary Al–Nb–Ti system is obtained by CALPHAD modelling of the Gibbs energy of all individual phases, taking into account experimental data on phase equilibria and thermodynamic properties published and complemented by own experiments. The description includes a re-evaluation of the constituent binary Al...
Article
The thermodynamic description of the binary system Al–Ti is obtained by modelling the Gibbs energy of all individual phases using the CALPHAD approach. The model parameters have been evaluated by means of the computer optimization module PARROT, available within Thermo-Calc, taking into account recent experimental data and critically assessed infor...
Article
Full-text available
The grain refinement achieved with low boron additions to selected TiAl-based alloys was investigated in unidirectional solidified samples by means of EBSD-orientation mapping of the α(Ti) phase, retained by quenching. The analysis shows that excellent grain refinement is achieved during the solid state transformation of the body centred β(Ti) into...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
The partial and the integral enthalpies of mixing of liquid ternary Al–Cr–Ni alloys have been determined by high temperature iso-peribolic calorimetry at 1718–1731 K. Measurements for ternary alloys were performed along 4 isopleths with xCr:xNi of 0.20:0.80, 0.50:0.50, 0.70:0.30, and 0.85:0.15. The results were analytically described by the thermod...
Article
The thermodynamic description of the ternary system B–Nb–Ti is obtained by modelling the Gibbs energy of all individual phases in the system using the CALPHAD approach. The model parameters have been evaluated by means of a computer optimization technique based on the available descriptions of the constituent binary systems B–Nb, B–Ti and Nb–Ti and...
Article
Thin silicon films are of great importance for large-area electronic applications, for example, as the basis for switching electronics in flat-panel display devices or as the active layer of solar cells. In this paper, we show that silicon nanoparticles have the potential to be used as raw material for further processing toward a microcrystalline s...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
Aiming to obtain a reliable description of the quaternary Al–B–Nb–Ti system, the thermodynamic descriptions of the constituent binary systems B–Nb and B–Ti are revised by modelling of the Gibbs energies of all individual phases using the CALPHAD approach and recent SGTE descriptions of the Gibbs energies of phases for pure elements. The model param...
Chapter
By the combination of computational thermodynamics (CALPHAD), phaese-field simulations and unidirectional solidification experiments a valuable way is show for understanding microstructure formation in multicompnent multiphase systems. Two ternary eutectic alloy systems Ag-Cu-Zn and In-Bi-Sn, respectively have been investigated. The thermodynaic de...
Conference Paper
Full-text available
Titanium aluminides containing high niobium additions emerged as an attractive alloy family for automotive and aero-engine applications. Their processing by near net shape casting is rather demanding, not only due to easy contamination but also due to the fact that microstructure formation during solidification and subsequent solid state transforma...
Article
{Sc,Ti}2M3Si alloys (M = Cr, Mn, Fe, Co, Ni) were investigated by X-ray powder and single crystal diffraction, optical microscopy and electronic density-functional theory. Structure determination from X-ray CCD-data from a single crystal of Ti2Co3Si and Rietveld refinements of X-ray powder diffraction data for Sc2M3Si (M = Fe, Co) and Ti2M3Si (M =...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Conference Paper
In this paper we present an experimental study of the influence of controlled fluid flow conditions during solidification on the morphology and spatial arrangement of intermetallic phases in the alloy Al-7wt.%Si-1wt.%Fe. The forced convections are induced by a rotating magnetic field with a magnetic induction of 6mT at a frequency of 50Hz. The tern...
Article
We study the directional-growth patterns of the transparent nonfaceted alloy succinonitrile-(D)camphor (SCN-DC) at eutectic concentration in thin and bulk samples using real-time observation methods. We measure in situ the minimum-undercooling spacing) lambda(m) and the small-spacing stability limit lambda(c) of the thin, quasi-lamellar patterns. W...
Article
The temperature of phase transformations, as well as the enthalpy of melting of 29 different alloys from the Bi–In–Sn system were measured by DSC using a Perkin–Elmer DSC-7 instrument. The following tie-triangles were characterized in terms of analysing the chemical composition of the phases in equilibrium, using energy dispersive X-ray analysis (E...
Article
{Sc,Ti}2M3Si alloys (M=Cr, Mn, Fe, Co, Ni) were investigated by X-ray powder and single crystal diffraction, optical microscopy and electronic density-functional theory. Structure determination from X-ray CCD-data from a single crystal of Ti2Co3Si and Rietveld refinements of X-ray powder diffraction data for Sc2M3Si (M=Fe, Co) and Ti2M3Si (M=Cr, Mn...
Article
Several key experiments were performed to determine the temperature of transformations of organic alloys from the ternary systems 2-amino-2-methyl-1,3-propanediol–(D)camphor–succinonitrile (AMPD-DC-SCN) and 2-amino-2-methyl-1,3-propanediol–neopentylglycol–succinonitrile (AMPD-NPG-SCN) by means of differential scanning calorimetry (DSC). The phase d...
Article
Full-text available
Recently, the prediction of structural degeneracy for the ground state of ZrMn2 by ab initio methods has stimulated research on this system. We investigated the structural and thermodynamic properties by single crystal and powder x-ray diffraction (at zero and high pressure) as well as by neutron powder diffraction, demonstrating that the C14 Laves...
Article
Full-text available
Technical Al-Si alloys always contain sufficient amounts of Fe and Mn, especially alloys made from scrap. During casting, Fe-containing intermetallics, such as Al-Fe, Al-Fe-Si and Al-Fe-Mn-Si phases, are formed between the aluminum dendrites. Fe and Mn-rich intermetallic phases are well known to be strongly influential on mechanical properties in A...
Article
Combined refinement of neutron powder, X-ray single crystal and powder diffraction data allows precise evaluation of symmetry and atom site occupation for the MgZn2-type Laves phase. For compositions Ti(Ni1-x,Al-x)(2) titanium atoms were found to fully occupy the 4f site, whilst Ni- and Al-atoms randomly share the 2a and 6h sub-lattice sites of spa...
Article
The enthalpies of formation of β and γ alloys of the Ag-Cu-Zn system were determined by dissolution calorimetry. The melting and solid-state transformation temperatures as well as the enthalpies of the order/disorder and β/ξ transformations were measured by differential scanning calorimetry. Thermodynamic descriptions are presented for the binary A...
Article
Full-text available
The partial enthalpies of dissolution of pure Ni, W and Ta in liquid ternary Ni–Ta–W alloys have been determined at (17735)K using a high temperature isoperibolic calorimeter. Measurements were performed in Ni-rich alloys (from 80 to 100 at.% Ni) along sections with constant Ta:W atomic ratios 1:0, 2:1, 1:2, and 0:1. The partial enthalpies and ther...
Article
Full-text available
Site preference and thermodynamic properties of the ternary Laves phase Ti(Fe1-xAlx)2 with MgZn2-type have been studied employing Rietveld refinement of X-ray and neutron powder diffraction data, X-ray single crystal data, and isoperibolic drop calorimetry techniques. A detailed relation between lattice parameters of Ti(Fe 1-xAlx)2 and the Al conte...
Article
Full-text available
Coupled, regular eutectic growth of α(Al) and Al2Cu from ternary Al-Cu-Ag liquid alloys is investigated with focus on the formation and the characteristics of eutectic cells in unidirectionally solidified, polycrystalline, bulk samples. The topologic anisotropy of the lamellar eutectic leads to destabilization along the lamellae with elongated cell...
Article
The temperature and enthalpy of transformations of organic alloys from the ternary systems (D)camphor–neopentylglycol–succinonitrile (DC–NPG–SCN) were measured by means of differential scanning calorimetry (DSC). The phase diagram of this ternary system was assessed via the CALPHAD approach using Thermo-Calc based on the thermodynamic descriptions...
Article
The temperature and enthalpy of transformations of organic alloys from the ternary system 2-amino-2-methyl-1,3-propanediol–(D)camphor–neopentylglycol (AMPD–DC–NPG) were measured by means of differential scanning calorimetry (DSC). The phase diagram of this ternary system was assessed via the CALPHAD approach using Thermo-Calc based on the thermodyn...
Article
Coupled, regular eutectic growth of α(Al) and Al2Cu from ternary Al-Cu-Ag liquid alloys is investigated with focus on the formation and the characteristics of eutectic cells in unidirectionally solidified, polycrystalline, bulk samples. The topologic anisotropy of the lamellar eutectic leads to destabilization along the lamellae with elongated cell...
Article
While thermodynamic data have been successfully assessed for an increasing number of alloy systems from equilibrium experiments using the CALPHAD approach, there is still a tremendous lack of melt diffusion and surface energy data, which are needed for simulation of solidification processes. In this paper we present an approach for determining liqu...
Conference Paper
Coupled, regular eutectic growth of alpha(Al) and Al(2)Cu from ternary Al-Cu-Ag liquid alloys is investigated with focus on the formation and the characteristics of eutectic cells in unidirectionally solidified, polycrystalline, bulk samples. The topologic anisotropy of the lamellar eutectic leads to destabilization along the lamellae with elongate...
Article
A technique widely used for the in situ observation of microstructure formation in transparent organic systems was applied to metallic alloys with low melting temperature. In the ternary eutectic alloy system In–Bi–Sn, we observed by light microscopy steady state and transient eutectic microstructure formation during unidirectional solidification i...