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A Study on iron-based amorphous alloys : alloy development, thermodynamics and soft magnetism

Citation

Liu, Xiao (2014) A Study on iron-based amorphous alloys : alloy development, thermodynamics and soft magnetism. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:11222013-151337813

Abstract

Metallic glass has since its debut been of great research interest due to its profound scientific significance. Magnetic metallic glasses are of special interest because of their promising technological applications. In this thesis, we introduced a novel series of Fe-based alloys and offer a holistic review of the physics and properties of these alloys. A systematic alloy development and optimization method was introduced, with experimental implementation on transition metal based alloying system. A deep understanding on the influencing factors of glass forming ability was brought up and discussed, based on classical nucleation theory. Experimental data of the new Fe-based amorphous alloys were interpreted to further analyze those influencing factors, including reduced glass transition temperature, fragility, and liquid-crystal interface free energy. Various treatments (fluxing, overheating, etc.) were discussed for their impacts on the alloying systems' thermodynamics and glass forming ability. Multiple experimental characterization methods were discussed to measure the alloys' soft magnetic properties. In addition to theoretical and experimental investigation, we also gave a detailed numerical analysis on the rapid-discharge-heating-and-forming platform. It is a novel experimental system which offers extremely fast heating rate for calorimetric characterization and alloy deformation.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:amorphous metal, metallic glass, iron, thermodynamics, crystallization, glass forming ability
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Materials Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Johnson, William Lewis
Thesis Committee:
  • Johnson, William Lewis (chair)
  • Fultz, Brent T.
  • Greer, Julia R.
  • Goddard, William A., III
Defense Date:12 November 2013
Record Number:CaltechTHESIS:11222013-151337813
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:11222013-151337813
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8033
Collection:CaltechTHESIS
Deposited By: Xiao Liu
Deposited On:27 Jan 2014 20:21
Last Modified:03 Mar 2016 21:41

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