G. Pottlacher

G. Pottlacher
Graz University of Technology | TU Graz · Institute of Experimental Physics

Dipl.Ing. Dr.

About

126
Publications
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2,261
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January 1982 - June 2014
Graz University of Technology
Position
  • ao.univ.Prof

Publications

Publications (126)
Article
Full-text available
NIST SRM 1155a is an AISI 316L stainless steel (Cr18–Ni12–Mo2) and Standard Reference Material (SRM) intended for use with test methods for elemental analysis. In a previous paper “Measurement of thermophysical properties of solid and liquid NIST SRM 316L stainless steel”, we already published reliable thermophysical properties of high temperature...
Article
Full-text available
In this work, we present normal spectral emissivity data of solid and liquid molyb-denum at a wavelength of 684.5 nm. The presented results are novel measurements on molybdenum, a material, which was already measured 15 years ago by our group. The present results indicate a lower emissivity in the liquid phase. The novel measurements were done with...
Article
Full-text available
W360 is a hot work tool steel produced by voestalpine BÖHLER Edelstahl GmbH & Co KG, a special steel producer located in Styria, Austria. Surface tension and density of liquid W360 were studied as a function of temperature in a non-contact, containerless fashion using the oscillating drop method inside an electromagnetic levitation setup. For both,...
Article
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The density as a function of temperature was determined for liquid iridium (Ir) and rhenium (Re) by means of shadow imaging in ohmic pulse-heating experiments. In addition to regular experiments at \(0.23\,\text {MPa}\), high-pressure experiments at static pressures between \(0.18\,\text {GPa}\) to \(0.30\,\text {GPa}\) were performed to increase t...
Article
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In this work, we perform high accuracy measurements of thermophysical properties for the National Institute of Standards and Technology standard reference material for 316L stainless steel. As these properties can be sensitive to small changes in elemental composition even within the allowed tolerances for an alloy class, by selecting a publicly av...
Article
Full-text available
Nickel is an important component in many alloys, so reliable surface tension data in the liquid phase are essential for simulation processes in the metal industry. First results for surface tension of liquid nickel from our working group by Aziz et al. [1], which led to the first publication on the topic of our Electromagnetic Levitation (EML) setu...
Article
In this study, some structure-sensitive thermophysical properties, namely, thermal conductivity, thermoelectric power, density and surface tension of liquid AlCu4TiMg alloy, as one of the most promising cast alloys to fabricate components for cars, aircraft and other complex engineering products, were investigated. Thermoelectric power was measured...
Article
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Density as a function of temperature was measured for the liquid transition metals niobium and tungsten by means of ohmic pulse-heating. The generated data are extensively compared to the existing literature data, and the uncertainty is critically assessed according to the guide to the expression of uncertainty in measurement (GUM). Starting from t...
Article
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This paper presents a new production method for a spherical and monocrystalline aluminum powder. Aluminum powder of irregular particle shapes was mixed with silica nanoparticles and heated to a temperature above the melting point of aluminum. Due to its molten state, high surface tension, and poor wettability, the aluminum particles were transforme...
Data
List of publications of G. Pottlacher
Article
Full-text available
In order to determine the density of tantalum over the entire liquid phase (at the pressure applied) and several hundred K into the super-heated region, the method of ohmic pulse-heating was applied. For this purpose, images of the thermal radial expansion of the resistively heated sample wires were taken with an adapted CCD system. A newly integra...
Article
Full-text available
The need for characterization of thermophysical properties of steel was addressed in the FFG-Bridge Project 810999 in cooperation with our partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes such as plastic deformation or remelting, additional and more accurate thermophysical property data...
Article
Full-text available
Ohmic pulse-heating with sub-microsecond time resolution is used to obtain thermophysical properties for aluminum in the liquid phase. Measurement of current through the sample, voltage drop across the sample, surface radiation, and volume expansion allow the calculation of specific heat capacity and the temperature dependencies of electrical resis...
Article
Full-text available
Zusammenfassung Für das Eisen-Nickel Legierungssystem wird die Oberflächenspannung in Abhängigkeit der Temperatur in der flüssigen Phase untersucht. Hierfür kommt an der Technischen Universität Graz (TU Graz) die Methode des oszillierenden Tropfens (engl.: oscillating drop, OD) in Kombination mit einer elektromagnetischen Levitations-Apparatur zum...
Article
Full-text available
Ti-6Al-4V is due to its high strength-density ratio a commonly used alloy in aerospace industry applications. But liquid phase data are scarce as preventing contaminations of the reactive high temperature melt during the investigation process poses a challenge. The thermophysical quantity density is of special interest since it is necessary input p...
Article
Full-text available
In this study, some structure-sensitive thermophysical properties, namely, electrical conductivity, thermal conductivity and thermoelectric power of liquid binary alloys Al33.3Mg66.7, Mg47.6Zn52.4 and Mg33.3Zn66.7 (all in wt.%), as the most promising cast alloys to fabricate components for cars, aircraft and other complex engineering products, were...
Article
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The surface tension of liquid Cu–5Sn (copper with 5wt% tin) in the temperature range from 1290K to 1560K was measured by an oscillating drop technique combined with electromagnetic levitation. The levitation device uses an inhomogeneous radiofrequency electromagnetic field inside a levitation coil to position and to heat metallic material. Eddy cur...
Data
Full-text available
Listning of my publications
Conference Paper
Full-text available
High temperature experimentation with solid and especially liquid specimens faces numerous difficulties. Traditional static steady state techniques for the measurement of thermophysical properties are generally limited to temperatures of about 2300 K. This limitation is a result of chemical interaction of the specimens with the containers, the loss...
Article
Manganin is the trademark name of the alloy Cu86Mn12Ni2. Despite its frequent usage in manufacturing processes, literature data are scarce particularly at higher temperatures. This work presents a set of thermophysical data of this alloy in a temperature range above its classic area of application up to the end of its liquid phase. For investigatin...
Article
Fast resistive pulse-heating techniques and electromagnetic levitation techniques are capable of determining thermophysical properties of metals in the liquid phase. These properties have become increasingly important as input data for modern numerical simulations. Among others, density is a very relevant parameter for e.g., casting modeling. Densi...
Article
The need for characterization of thermophysical properties of steel and nickel-based alloys was addressed in the FFG-Bridge Project 810999 in cooperation with a partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes, such as remelting or plastic deformation, additional, and more accurate data...
Article
The oscillating drop technique is a well-established method for the measurement of surface tension. In this work an electromagnetic levitation device is used to measure the surface tension of nickel by means of the oscillating drop technique. An electromagnetic levitation device employs an inhomogeneous radio-frequency electromagnetic field inside...
Article
Inert purge gases are commonly used in high-temperature differential scanning calorimetry (DSC) to prevent sample oxidation. However, little research has been published regarding their influence on DSC measurements and the corresponding uncertainties. By comparing helium, nitrogen, and argon—three common purge gases with significantly different phy...
Data
Full-text available
Zeitschrift fuer Metallkunde; v. 73(9) p. 548-551; ISSN 0044-3093; Sep 1982
Article
We describe current approaches to thermodynamic modelling of liquids for the CALPHAD method, the use of available experimental methods and results in this type of modelling, and considerations in the use of atomic-scale simulation methods to inform a CALPHAD approach. We begin with an overview of the formalism currently used in CALPHAD to describe...
Article
Measurements of thermophysical properties of liquid metals are demanding and thus rare. A recently published collection provides high temperature data for a set of 22 metals. Although the measurements concern data in the range up to 5000 K, the critical region however, is mostly far beyond the region accessible experimentally at present, with the e...
Article
An electromagnetic levitation device has been recently constructed by the thermophysics and metalphysics group at TU Graz, Austria and first investigations of copper in the liquid phase have been carried out. Data for temperature dependence of surface tension will be presented in this work and compared to results from literature. The value obtained...
Article
Full-text available
Optical and thermophysical properties of pure metals at the melting point and in the liquid phase are of general interest for technological applications. This is especially true for those metals that are commonly applied. Many of these elements are used either in their pure form or as alloying components. Due to their widespread use in industry an...
Article
Platinum and copper along with their alloys have been used in a broad range of applications including jewelry, coinage, electrical and electronic devices, and many others. Their thermophysical properties play an important role in casting processes and are required as input data for casting simulation. The focus of this work was to investigate these...
Article
Our work group has rendered outstanding services in the field of dynamic pulse calorimetry within the last thirty years to obtain thermophysical properties of liquid metals and alloys. Today, only few more experiments on pure metals are to be expected, because almost all metallic elements, which are suitable for our pulse-heating system so far, hav...
Article
Within this study, the normal spectral emissivity at melting and in the liquid state of the highly alloyed steel HS2-9-1-8 at 684.5 nm is presented. Measurements were performed with a division-of-amplitude photopolarimeter, as part of a fast ohmic pulse heating system reaching heating rates of about 108 K · s−1. The determined data show an increasi...
Article
Full-text available
Thermophysical properties of platinum and four platinum alloys namely, Pt-4Cu Pt96Cu4, Pt68Cu32, Pt50Cu50 and Pt25Cu75 are investigated in the solid and in the liquid phase by a fast pulse-heating technique. In this technique wire shaped samples are resistively volume heated as part of fast capacitor discharge circuit. With heating rates up to 10^8...
Article
Full-text available
The workgroup of subsecond thermophysics in Graz has a long tradition in performing fast pulseheating experiments on metals and alloys. Thereby, wire-shaped specimens are rapidly heated (108 K/s) by a large current-pulse (104 A). This method provides thermophysical properties like volume-expansion, enthalpy and electrical resistivity up to the end...
Article
For the containerless processing of high temperature metallic melts the electromagnetic levitation technique, which utilizes high frequency alternating magnetic fields for the contactless, inductive positioning and heating of electrically conducting samples, is well established. For the contactless measurement of surface tension and viscosity of le...
Article
During fast pulse-heating experiments an electrically conducting sample is heated rapidly by the passage of a large current pulse. Heating continues until the material evaporates (thus leading to the so-called 'wire-explosion'). Simultaneous measurements of temperature, voltage drop, current, and thermal expansion deliver thermophysical properties...
Article
Two CuMnNi alloys, both similar to Manganin® in chemical composition, were studied in this work. By means of DTA measurements, the solidus and liquidus temperatures were measured for both alloys. To determine thermal volumetric expansion, specific electrical resistivity and specific enthalpy in the temperature range from 1000 K to 1900 K, the fast...
Article
The presented work describes the application of a microsecond division of amplitude photopolarimeter (μ-DOAP) within a fast ohmic pulse heating system to obtain optical constants (?, k) and further normal spectral emissivity at the given laser wavelength of 684.5 nm. Other then most ellipsometers this system has to operate without any moving parts...
Conference Paper
Full-text available
Article
Thermophysical properties (e.g., specific enthalpy, heat of fusion, electrical resistivity, thermal volume expansion) are measured in the liquid phase up to very high temperatures by an extreme fast pulse-heating method. Heating rates of about 108 K · s−1 are applied by self-heating of wire-shaped metallic specimens with a current of approximately...
Article
The fast pulse-heating method provides a possibility to investigate thermophysical properties in the liquid state of electrically conducting materials in terms of a containerless measurement technique. Thereby wire-shaped specimens are rapidly heated by the passage of a large current pulse. This leads to heating rates of 108K/s and an experimental...
Article
Normal spectral emissivity measurements at 684.5 nm for two steels and two nickel-based superalloys at the melting transition and in the molten state are reported in this study. The measurements were performed using a division-of-amplitude photopolarimeter on a microsecond time-scale which is part of a resistive pulse-heating experiment. Emissivity...
Article
Full-text available
The so-called platinum metals are Ru, Rh, Pd, Os, Ir and Pt. Our workgroup has already published data on Pd, Ir and Pt. The present work will focus on measurements of the thermophysical properties of rhodium, which have been carried out recently. The scarce literature data available emphasize the need for new measurements. Using a rapid pulse-heati...
Article
This chapter discusses the thermophysical properties of solid and liquid metals and alloys. Thermophysical properties are a selection of mechanical, electrical, optical, and thermal material properties of metals and alloys (and their temperature dependencies) that are relevant in industrial, scientific, and metallurgical applications. The chapter f...
Article
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Objective of the collaboration of TU Graz and DLR Cologne is the measurement of specific electrical resistivity comparing pulse-heating and levitation results. The TU Graz measurements on V, Nb, Ta, Mo and W will be presented and discussed with regard to volume expansion and resistivity.
Article
Numerical simulation of fluid flow, heat transfer, solidification or thermal induced stresses have gained a tremendous significance in steel working industry branches. With the advent of adequate computing power, full three-dimensional calculation of the determining physical equations have become possible. A major drawback of these simulation techn...
Article
Numerical simulation of vacuum arc re-melting, pressurized or protective electro-slag re-melting, and ingot casting have become quite important in the metal industry. However, a major drawback of these simulation techniques is the lack of accurate thermophysical properties for temperatures above 1,500K. Heat capacity, heat of fusion, density, and t...
Article
Wire shaped samples of commercially available Hf-3%Zr are resistively volume heated as part of a fast capacitor discharge circuit. Time resolved electrical measurements with sub-μs resolution include the current through and the voltage drop across the specimen. Surface radiance from the sample (to measure the temperature) is detected by pyrometers...
Article
Pulse-heating techniques are capable of measuring thermophysical properties of electrically conducting samples from room temperature up into the liquid state. These properties are of technological interest for modern numeric simulations, e.g., casting simulations. Such devices have been developed and greatly improved since their first technological...
Article
Electrical Resistivity Measurement of High Temperature Metallic Melts is an Austrian Space Applications Programme (ASAP) project, sponsored by the FFG. The project's main intent is the refinement of electrical resistivity data via a comparison between two very different experiments: fast pulseheating and electromagnetic levitation. The latter is pl...
Article
Liquid state densities and electrical resistivities of pure copper and nickel as well as some of their binary alloys in the vicinity of the constantan mixing ratio (Cu53Ni47 at%) were measured by electromagnetic levitation and pulse-heating techniques. The experiments were performed as part of a joint project between the German Aerospace Center (DL...
Article
Nimonic 80A is a nickel–chromium alloy which is strengthened by additions of titanium and aluminum. The alloy is used for high temperature, high-strength applications. This superalloy is used in gas turbine hot section components, for hot-working applications and forging hammers.This is the third paper reporting thermophysical properties of Nimonic...
Article
A μs-DOAP (division-of-amplitude photopolarimeter), operating without any moving devices, within a pulse-heating setup is used to access normal spectral emissivity at the melting-point and in the liquid phase. Within this study, measurements were performed for noble metals gold and silver as well as for copper, reporting normal spectral emittance a...
Article
Although vanadium is commonly used as an additive in the steel production, literature data for thermophysical properties of vanadium around the melting point are sparse and show, where available a variation over a wide range. This manifests especially in the melting temperature (variation of ±30K), heat of fusion, or specific enthalpy.This recent w...
Article
An ohmic pulse-heating experiment together with radiometry andμs-photopolarimetry is deployed at the Institute of Experimental Physics, Graz University of Technology, to obtain temperature-dependent thermophysical properties of conducting samples in the solid and molten states. This experimental setup has been used within the present work to gather...
Article
In a previous paper it was shown that the normal spectral emissivity at 684.5 nm of a binary alloy can be lower than that of the pure constituent components. For the actual probes it was found that the observed values of normal spectral emissivity of the alloys are in between or higher than those of the pure constituent components. Experiments were...
Article
Nimonic 80A is a nickel-chromium alloy which is strengthened by additions of titanium and aluminium. The alloy is used for high temperature, high strength applications. Wire shaped Nimonic 80A samples are resistively volume heated as part of a fast capacitor discharge circuit. Time resolved measurements with sub-μs resolution of current through the...
Article
Full-text available
The results from fast-pulse heating experiments (of duration 60 μs) performed on pure palladium are presented. Thermophysical properties derived include specific enthalpy, enthalpy of fusion, electrical resistivity, isobaric heat capacity, thermal conductivity and thermal diffusivity, over a range of temperatures from the melting transition up to s...
Article
Within the present work, recent investigation carried out with a fast pulse-heating technique on silver, copper and the Ag–28Cu binary alloy in the solid and the molten states are presented.Properties like enthalpy or electrical resistivity of a pulse-heated sample can be obtained for a wide temperature range (solid state up into the liquid state)...
Article
Full-text available
Ti-6Al-4V (TA6V) titanium alloy is widely used in industrial applications such as aeronautic and aerospace due to its good mechanical properties at high temperatures. Experiments on two different resistive pulse heating devices (CEA Valduc and TU-Graz) have been carried out in order to study thermophysical properties (such as electrical resistivity...
Article
Ti-6Al-4V (TA6V) titanium alloy is widely used in industrial applications such as aeronautic and aerospace due to its good mechanical properties at high temperatures. Experiments on two different resistive pulse heating devices (CEA Valduc and TU-Graz) have been carried out in order to study thermophysical properties (such as electrical resistivity...
Article
Since the 1960s, resistive pulse self-heating techniques, associated with 10<sup align="right"> 4 </sup> - 10<sup align="right"> 10 </sup> K.s<sup align="right"> -1 </sup> heating rates, have been widely developed in order to study both solid and liquid states of pure and alloyed metals at very high temperature (up to 10,000 K). This paper is a rev...
Article
Normal spectral emissivity at 684.5 nm of the liquid binary system Fe–Ni was measured by means of a fast ohmic pulse heating technique combined with fast ellipsometry. The experimental values observed of all liquid alloys are dependent on composition and temperature in the entire range of mixing. Spectral emissivity was measured for pure iron, Fe90...
Article
The electric and temperature fields in a pulse-heated wire with a quadratic cross section are calculated analytically. The quick increase of the current through the wire during the pulse-heating process results in a nonuniform electric field (skin effect), and thus also a nonuniform temperature field over the wire cross section. By means of a typic...
Article
Prediction methods for thermophysical properties of metals and alloys such as emissivity are of great interest not only for science but also for the metal working industry as time-consuming and often expensive measurements may not be required. As recent results have shown, an assumed Hagen–Rubens relation for the prediction of emissivity based on e...
Article
Measurements of thermophysical properties such as enthalpy, electrical resistivity, and specific heat capacity as a function of temperature starting from the solid state into the liquid phase for W, Nb, and Ti are presented in this work. An ohmic pulse-heating technique allows measurements of enthalpy and electrical resistivity from room temperatur...
Article
Magnesium alloy AE42 (Mg with 4% Al and 2% rare earths) is used for the production of high-temperature creep-resistant castings. Its thermophysical properties are used as input parameters for the numerical simulation of the casting process by finite methods. Measurements of specific heat capacity, electrical resistivity, and linear thermal expansio...
Article
The results of an inter laboratory comparison of thermal conductivity, thermal diffusivity, specific heat capacity, and thermal expansion measurements on austenitic stainless steel in the temperature range between 20 and 1000°C are presented here. Mean values are presented for the physical properties studied. Reliable relative expanded uncertaintie...
Article
Full-text available
Polarimetric emissivity measurements adapted for a rapid pulse heating setup and recent results of normal spectral emissivity at 684.5nm for molybdenum at melting and in the liquid phase are presented. Also reported is a complete set of thermophysical data (specific enthalpy, isobaric heat capacity, electrical resistivity, thermal conductivity, and...
Article
Measurements of the enthalpy, electrical resistivity, and specific heat capacity as a function of temperature starting from the solid state up into the liquid phase for Fe, Ni, and Pt are presented. Two different measurement approaches have been used within this work: an ohmic pulse-heating technique, which allows – among others – the measurement o...
Article
With ohmic pulse heating the measurement of thermophysical data of electrically conducting materials far into the fluid stage are possible. Heating rates up to 108K/s are achieved, and the fluid state is achieved after about 30μs. Within this short time the geometry of the sample will neither be destroyed through force of gravity, instabilities nor...
Conference Paper
Full-text available
The commercial implementation of TiAl alloys is currently hampered by difficulties in melting and casting them. Computer modelling has much to offer for helping to understand and optimise the widely-used Induction Skull Melting and investment casting techniques, but its application is limited by the lack of information of the thermo-physical proper...