Eutectic-to-metallic glass transition in the Al-Sm system

Kalay, Yunus Eren
Trivedi, R.
A systematic experimental study is carried out to investigate microstructure selection over a very wide range of undercooling at the interface in the Al-Sm system by using a combination of the Bridgman, laser and melt spinning techniques, which give increasing interface undercooling. Eutectic microstructure forms at low undercooling, while metallic glass forms at very large undercooling. Experiments are designed to obtain a sharp transition from the eutectic to glass during the growth of eutectic as the interface undercooling increases with growth. The eutectic spacing at the transition is characterized, and the results are analyzed by using a model of eutectic growth that incorporates non-equilibrium effects at the interface. It is shown that a very large undercooling at the interface, required for glass formation, is obtained due to the combined effects of the sharp decrease in the diffusion coefficient, or the sharp increase in viscosity of the liquid, with undercooling in this system and the large undercooling required for the attachment kinetics at the compound liquid interface in the eutectic structure. Published by Elsevier Ltd. on behalf of Acta Materialia Inc.


Analyzing the Information Distribution in the fMRI Measurements by Estimating the Degree of Locality
Onal, Itir; Ozay, Mete; Firat, Orhan; GİLLAM, İLKE; Yarman Vural, Fatoş Tunay (2013-07-07)
In this study, we propose a new method for analyzing and representing the distribution of discriminative information for data acquired via functional Magnetic Resonance Imaging (fMRI). For this purpose, we form a spatially local mesh with varying size, around each voxel, called the seed voxel. The relationship among each seed voxel and its neighbors is estimated using a linear regression model by minimizing the square error. Then, we estimate the optimal mesh size that represents the connections among each ...
Interband optical absorption obtained by pseudopotential method for type-II InAs/GaSb SL photodetectors
Akel, Kazim; Hoştut, Mustafa ; Akın, Tayfun; Ergun, Yuksel (2021-05-01)
We have calculated interband optical absorption for InAs/GaSb based type-II superlattice (SL) structures. The empirical pseudopotential method (EPM) has been used as an alternative to the k.p method since it is less sophisticated while providing similar results in the mid wavelength infrared range and long wavelength infrared range atmospherics bands for comparison. EPM results show that the bandgap wavelengths of SLs have been predicted with the underestimating of 0.4 mu m. This corresponds to an uncertain...
Micromechanical characterization of metallic glass — crystalline nanocomposite coatings
Abboud, Mohammad; Özerinç, Sezer; Kalay, Yunus Eren; Department of Micro and Nanotechnology (2018)
Amorphous/crystalline nanolayers provide an effective model system to study the mechanical behavior and size effects of metallic glasses and crystalline metals in confined geometries. They also provide an advantageous structure for improving the ductility of amorphous metals while maintaining their outstanding strength. Combination of high strength and ductility make these nanocomposites promising materials as wear resistant coatings. The structure-property relationship in Amorphous/Crystalline nanolayers c...
Pentacene Multilayers on Ag(111) Surface
METE, ERSEN; Demiroglu, Ilker; Danışman, Mehmet Fatih; Ellialtioglu, Sinasi (American Chemical Society (ACS), 2010-02-18)
The structural profiles and electronic properties of pentacene (C22H14) multilayers on Ag(111) surface has been studied within the density functional theory framework. We have performed first-principle total energy calculations based on the projector-augmented wave method to investigate the initial growth patterns of pentacene (Pn) on Ag(111) surface. In its bulk phase, pentacene crystallizes with a triclinic symmetry while a thin film phase having an orthorhombic unit cell is energetically less favorable b...
Multidimensional quantum tunneling in the Schwinger effect
Dumlu, Cesim K. (American Physical Society (APS), 2016-03-22)
We study the Schwinger effect, in which the external field having a spatiotemporal profile creates electron-positron pairs via multidimensional quantum tunneling. Our treatment is based on the trace formula for the QED effective action, whose imaginary part is represented by a sum over complex worldline solutions. The worldlines are multiperiodic, and the periods of motion collectively depend on the strength of spatial and temporal inhomogeneity. We argue that the classical action that leads to the correct ...
Citation Formats
N. WANG, Y. E. Kalay, and R. Trivedi, “Eutectic-to-metallic glass transition in the Al-Sm system,” ACTA MATERIALIA, pp. 6604–6619, 2011, Accessed: 00, 2020. [Online]. Available: