Supercooled Liquid
Mostrando 1-12 de 19 artigos, teses e dissertações.
-
1. Consolidation of Fe-Based Metallic Glass Powders by Hot Pressing
An alternative route to obtain bulk metallic glasses is by consolidation of metallic glass powders by deforming these materials in the temperature interval between the crystallization temperature and the glass transition temperature, where the material flows with a reduced viscosity. In the present work, bulk parts of the Fe43.2Co28.8B19.2Si4.8Nb4 alloy were
Mat. Res.. Publicado em: 17/01/2019
-
2. The Effects of High Magnetic Field Annealing on the Structural Relaxation of Fe71(Nb0.8Zr0.2)6B23 Bulk Metallic Glass
Fe-based magnetic metallic amorphous and nanocomposites have excellent soft magnetic properties including greater magnetization and magnetic permeability compared with crystalline alloys, especially at high operation frequency and temperature. The high magnetic field (HMF) up to 12T is introduced to the heat annealing of Fe71(Nb0.8Zr0.2)6B23 bulk metallic gl
Mat. Res.. Publicado em: 04/12/2015
-
3. Hot Consolidation of Partially Amorphous Cu-Ti Based Alloy: a Comparison Between Hot Extrusion and Hot Compaction by Sintering
Consolidation of amorphous powders, which take advantage of the supercooled liquid region, is an alternative way to overcome the size limitation in marginal metallic glasses. Cu36Ti34Zr22Ni8based amorphous powders were obtained during high energy ball-milling. The analyses revealed that amorphous structures of powders and ribbons are quite different and this
Mat. Res.. Publicado em: 2015-06
-
4. Simulações de líquidos super-resfriados via dinâmica molecular
This work presents the study of two models of glass-forming liquids using molecular dynamics simulations. The first model aims to analyze the effects on glassy dynamics which allow the enhancement of the glass formability on metallic glass formers. The Pd45Ni55 binary alloy and the Pd35Ni55Pt10 ternary one are modeled via the Embedded Atom method interaction
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/10/2012
-
5. Stability of an amorphous alloy of the Mm-Al-Ni-Cu system
An investigation was made of the stability of melt-spun ribbons of Mm55Al25Ni10Cu10 (Mm = Mischmetal) amorphous alloy. The structural transformations that occurred during heating were studied using a combination of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Crystallization took place through a multi-stage process. The first stage of
Mat. Res.. Publicado em: 30/08/2012
-
6. Consolidation of the Cu46Zr42Al7Y5 amorphous ribbons and powder alloy by hot extrusion
The amorphous Cu46Zr42Al7Y5 alloy presents large supercooled liquid region (ΔT X = 100 K), with a viscosity of about 10(6) N.s/m² where the material can flow as a liquid, making it possible an easy deformation in this temperature region. The aim of this work was to analyze processing routes to produce bulks of metallic glasses. Two kinds of materials were
Mat. Res.. Publicado em: 09/08/2012
-
7. New Zr-based glass-forming alloys containing Gd and Sm
The effect of minor additions of Gd and Sm on the glass-forming ability (GFA) of Cu-Zr-Al alloys is investigated here. The rationale for these additions is the fact that the atomic size distribution can increase GFA by changing the topology of the alloy as a function of cluster stability, which is tied to the electronegativity and ionic and covalent nature o
Mat. Res.. Publicado em: 09/08/2012
-
8. Selection of compositions with high glass forming ability in the Ni-Nb-B alloy system
A combination of an extension of the topological instability "λ criterion" and the "average electronegativity" has been recently reported in the literature to predict compositions with high glass-forming ability (GFA). In the present work, both criteria have been applied to select the Ni61.0Nb36.0B3 alloy with a high glass-forming ability. Ingots were prepa
Mat. Res.. Publicado em: 07/08/2012
-
9. Quantum effects in water: proton kinetic energy maxima in stable and supercooled liquid
A strong temperature dependence of proton mean kinetic energy was observed for liquid water around the density maximum and for moderately supercooled water. Line shape analysis of proton momentum distribution, determined from deep inelastic neutron scattering measurements, shows that there are two proton kinetic energy maxima, one at the same temperature of
Brazilian Journal of Physics. Publicado em: 2009-06
-
10. Atomistic simulations of supercooled gallium / Simulações atomisticas do galio super-resfriado
Recently, the existence of a liquid-liquid transition in pure substances has been proposed as an explanation of anomalous behaviors such as the increase of response functions (isothermal compressibility, coefficient of thermal expansion, specific heat) with decreasing temperature displayed by some liquids. The existence of this type of transition has been de
Publicado em: 2009
-
11. Heat and mass transfer in two-phase flow around airfoils with aeronautical anti-ice systems. / Transferência de calor e massa no escoamento bifásico em torno de aerofólios equipados com sistemas de antigelo aeronáuticos.
It is required to prevent ice accretion on wings and horizontal stabilizers because it may cause aerodynamic performance degradation, weight increase, flight control difficulties and, in critical cases, may lead to operational safety margins reduction. When aircraft flies through clouds containnig supercooled water droplets, which are in metastable equilibri
Publicado em: 2009
-
12. A study of cooling in a system with several ground states. / Estudo do resfriamento em um sistema com múltiplos estados fundamentais
We study a coupled two level systems as a model that imitate the behavior of supercooled liquids that become structural glasses under cooling. In the equilibrium the model shows a liquid phase and a crystalline phase with many grouond states. The model is defined on a square lattice and to each site a stochastic Ising variable is associated. The feature that
Publicado em: 2007