Investigation of solidification and crystallization of iron based bulk amorphous alloys

Download

index.pdf

Date

2004

Author

Erdiller, Emrah Salim

Metadata

Show full item record

Item Usage Stats

214
views

91
downloads

The aim of this study is to form a theoretical model for simulation of glass forming ability of Fe ? Based bulk amorphous alloys, to synthesize Fe ? based multicomponent glassy alloys by using the predictions of the theoretical study, and to analyze the influence of crystallization and solidification kinetics on the microstructural features of this amorphous alloys. For this purpose, first, glass forming ability of Fe ? (Mo, B, Cr, Nb, C) ? X ( X = various alloying elements, selected from the periodic table) ternary alloy systems were simulated for twenty different alloy compositions by using the electronic theory of alloys in pseudopotential approximation and regular solution theory. Then, by using the results of the theoretical study, systematic casting experiments were performed by using centrifugal casting method. The alloying elements were melted with induction under argon atmosphere in alumina crucibles and casted into copper molds of different shapes. Characterization of the cast specimens were performed by using DSC, XRD, SEM, and optical microscopy. Comparison of equilibrium and nonequilibrium solidification structures of cast specimens were also performed so as to verify the existence of the amorphous phase. Good agreement of the results of experimental work, with the predictions of the theoretical study, and the related literature was obtained.

Subject Keywords

Alloys., Amorphous substances.

URI

http://etd.lib.metu.edu.tr/upload/3/1096585/index.pdf
https://hdl.handle.net/11511/13963

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Characterization and fabrication of silicon thin films for solar cell applications Karaman, Mehmet; Turan, Raşit; Ünalan, Hüsnü Emrah; Department of Eurasian Studies (2011) In this thesis study, fabrication and characterization of silicon thin films prepared by magnetron sputtering and electron beam evaporation for solar cell applications have been investigated. In the first part of the study, magnetron sputtering method was used to fabricate thin hydrogenated amorphous silicon (a-Si:H) film on a Si substrate. Some samples were prepared on glass substrate for the basic characterizations like transmission and resistivity. Dark and illuminated I-V characteristics of the silicon ...
Synthesis and characterization of copper based bulk amorphous alloys Erdem, Mermer; Akdeniz, Mahmut Vedat; Mekhrabov, Amdulla O.; Department of Metallurgical and Materials Engineering (2013) Copper based bulk metallic glasses (BMG’s) are one of the promising advanced materials due to their unique mechanical properties, high glass forming ability (GFA) and low cost. In this thesis, the aim is to synthesize Cu-Hf based BMG’s and to investigate the crystallization behavior. Moreover, the crystallization kinetics by means of activation energies, critical cooling rate, nanocrystallization and Avrami exponents have been studied. Cu70Hf30 and Cu50Hf50 binary alloys were produced via arc melting with s...
Theoretical prediction of bulk glass forming ability (BGFA) of Ti-Cu based multicomponent alloys SUER, Sila; Mehrabov, Amdulla; Akdeniz, Mahmut Vedat (Elsevier BV, 2009-03-01) The bulk glass forming ability (BGFA) of Ti-Cu based multicomponent alloys has been evaluated via theoretical modeling and computer simulation studies based on a combination of electronic theory of alloys in the pseudopotential approximation and the statistical thermodynamical theory of liquid alloys The. magnitude of atomic ordering energies, calculated by means of the electronic theory of alloys in the pseudopotential approximation, was subsequently used for calculation of the key thermodynamic parameters...
Simulation of crystallization and glass formation processes for binary Pd-Ag metal alloys Kart, HH; Uludogan, M; Cagin, T; Tomak, Mehmet (2003-09-12) Glass formation and crystallization process of Pd-Ag metallic alloys are investigated by means of molecular dynamics simulation. This simulation uses the quantum Sutton-Chen (Q-SC) potential to study structural and transport properties of Pd-Ag alloys. Cooling rates and concentration effects on the glass formation and crystallization of binary alloys considered in this work are investigated. Pd-Ag alloys show the glass structure at fast cooling rates while it crystallizes at slow cooling rates. Increment of...
Investigation of structural, electronic, magnetic and lattice dynamical properties for XCoBi (X: Ti, Zr, Hf) Half-Heusler compounds Surucu, Gokhan; IŞIK, MEHMET; CANDAN, ABDULLAH; Wang, Xiaotian; Güllü, Hasan Hüseyin (Elsevier BV, 2020-06-15) Structural, electronic, magnetic, mechanical and lattice dynamical properties of XCoBi (X: Ti, Zr, Hf) Half-Heusler compounds have been investigated according to density functional theory and generalized gradient approximation. Among alpha, beta and gamma structural phases, gamma-phase structure has been found as the most stability characteristics depending on the calculated formation enthalpies, energy-volume dependencies and Cauchy pressures. Energy-volume plots of possible magnetic orders of gamma-phase ...

Citation Formats

E. S. Erdiller, “Investigation of solidification and crystallization of iron based bulk amorphous alloys,” M.S. - Master of Science, Middle East Technical University, 2004.