18 Result(s)
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Article
A. K. Gangopadhyay
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Open AccessElectromagnetic levitation containerless processing of metallic materials in microgravity: rapid solidification
Space levitation processing allows researchers to conduct benchmark tests in an effort to understand the physical phenomena involved in rapid solidification processing, including alloy thermodynamics, nucleati...
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Open AccessDemonstration of the effect of stirring on nucleation from experiments on the International Space Station using the ISS-EML facility
The effect of fluid flow on crystal nucleation in supercooled liquids is not well understood. The variable density and temperature gradients in the liquid make it difficult to study this under terrestrial grav...
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Surface Tension and Viscosity of Cu50Zr50 Measured by the Oscillating Drop Technique on Board the International Space Station
The surface tension and viscosity of equilibrium and supercooled liquids of Cu50Zr50 were measured in the containerless electromagnetic levitator ISS-EML in the European space laboratory Columbus on board the Int...
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Recent progress in understanding high temperature dynamical properties and fragility in metallic liquids, and their connection with atomic structure
The advent of containerless processing techniques has opened the possibility of high quality measurements of equilibrium and metastable liquids. This review focuses on the structure and dynamics of metallic li...
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Measurements of the Temperature-Dependent Total Hemispherical Emissivity Using an Electrostatic Levitation Facility
Among the three fundamental processes of heat transfer (conduction, convection, and radiation), radiation is the most dominant at high temperatures. The total hemispherical emissivity is an important property ...
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Thermal Evaporation Loss Measurements on Quasicrystal (Ti–Zr–Ni) and Glass Forming (Vit 106 and Vit 106a) Liquids
Thermal evaporation loss measurements made using the electrostatic levitation (ESL) technique for one binary Ti–Zr, two ternary Ti–Zr–Ni, and two glass-forming (Vit 106 and Vit 106a) alloy liquids are reported...
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Nucleation and Thermophysical Properties of Glass-Forming Liquids
The intimate links among structure, nucleation, and thermophysical properties are demonstrated from a few select experiments on high-melting-temperature metallic alloy liquids, made possible by containerless p...
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Functional nanostructures through nanosecond laser dewetting of thin metal films
Techniques for processing nanoscale metallic structures with spatial order and tunable physical characteristics, such as size and microstructure, are paramount to realizing applications in the areas of magneti...
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Nanoparticle ordering by dewetting of Co on SiO2
Most metals on SiO2 have a finite contact angle and are therefore subject to dewetting during thermal processing. The resulting dewetting morphology is determined primarily by nucleation and growth or instabiliti...
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Surface Tension and Viscosity of Quasicrystal-Forming Ti–Zr–Ni Alloys
Recent X-ray scattering measurements show that icosahedral short-range order in Ti–Zr–Ni alloys is responsible for a change in phase selection from the stable C14 Laves phase to the quasicrystalline icosahedra...
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Undercooling And X-Ray Structural Studies Of Ti-Zr-Ni Liquids
Maximum undercooling results for the icosahedral phase (i-phase), polytetrahedral C14 Laves phase, and solid solution phases are presented as a function of composition in Ti-Zr-Ni liquids. Containerless proces...
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Phase Diagram and Electrostatic Levitation Undercooling Studies of Polytetrahedral Phases in Ti−Fe−Si−O and Ti−Zr−Ni Alloys
New information on the phase diagrams of Ti-Fe-Si-O and Ti-Zr-Ni alloys near the quasicrystal and rational approximant compositions is presented. α(TiFeSiO), the 1/1 rational approximant, is shown to form in a...
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Crystallization of Al-Gd-La-Ni Metallic Glasses
The crystallization kinetics of Al-Gd-La-Ni metallic glasses to nanostructured phases are analyzed using differential scanning calorimetry and transmission electron microscopy. In a narrow alloy composition ra...
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Characterization of silicon-stabilized amorphous hydrogenated carbon
The characterization of a modified form of diamondlike carbon, referred to as silicon-stabilized amorphous hydrogenated carbon (Si-AHC), is described. Auger electron spectroscopy, electron probe microanalysis,...
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CO2 decomposition kinetics of YBa2Cu3O7−x via in situ electrical conductivity measurements
In situ electrical conductivity measurements were employed to study the kinetics of decomposition of YBa2Cu3O7−x in flowing 5% CO2/95% O2 atmosphere at 815 °C. Three regimes could be observed in the decay of the ...
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Reduction in Wear Rate of α-Alumina and Silicon Nitride by Diffusional Surface Modification
The surface regions of α-alumina and hot pressed silicon nitride were modified by suitable alloying in order to improve their wear resistance. The surface modification in polycrystalline α-alumina was done by ...
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Residual resistivity in Ni-Fe-Cr/V alloys and the two-current model
The resistivity of a large number of Ni-Fe-Cr/V alloys has been measured at 77 K. An attempt has been made to explain the concentration dependence of resistivity in the light of Mott’s two-current model. It is...
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Assessment of wear mechanisms in grinding media
The effect of grinding media composition, mineral type, and slurry environment on the wear rate of various grinding media (balls) are discussed. Sufficient wear data have been obtained and correlated. Modes of...
