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Microstructure and Property Evolution in Cold Worked Equiatomic Fe-Pd During Isothermal Annealing.

Deshpande, Anirudha Rajendra (2004) Microstructure and Property Evolution in Cold Worked Equiatomic Fe-Pd During Isothermal Annealing. Master's Thesis, University of Pittsburgh.

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    Abstract

    In this work the evolution of microstructure and magnetic properties in cold deformed, equiatomic FePd during isothermal annealing has been studied. During annealing of the disordered cold deformed FePd at temperatures below the critical ordering temperature, Tc = 928 K (655 ºC), concomitant annealing and ordering (FCC -> L1sub0) reactions take place. The effects of the processing parameters - stored energy of cold work and temperature - on microstructural and property evolution are investigated. The combined solid state reaction (CR) produces complex microstructures that exhibit enhanced magnetic hardness (coercivity) relative to the conventionally processed material. The magnetic age hardening response of the CR processed FePd has been reported. For fully equiaxed polycrystalline microstructures of the ordered FePd phase a correlation between the average grain size and the coercivity has been observed. Based on these purely microstructural observations a qualitative coercivity mechanism analysis has been performed in order to elucidate the origin of the decrease in magnetic hardness (coercivity) in the overaged condition.


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    Item Type: University of Pittsburgh ETD
    ETD Committee:
    ETD Committee TypeCommittee MemberEmail
    Committee ChairWiezorek, Jorg M Kwiezorek@pitt.edu
    Committee MemberSoffa, W Awsoffa@pitt.edu
    Committee MemberBarnard, J Ajbarnard@engr.pitt.edu
    Title: Microstructure and Property Evolution in Cold Worked Equiatomic Fe-Pd During Isothermal Annealing.
    Status: Unpublished
    Abstract: In this work the evolution of microstructure and magnetic properties in cold deformed, equiatomic FePd during isothermal annealing has been studied. During annealing of the disordered cold deformed FePd at temperatures below the critical ordering temperature, Tc = 928 K (655 ºC), concomitant annealing and ordering (FCC -> L1sub0) reactions take place. The effects of the processing parameters - stored energy of cold work and temperature - on microstructural and property evolution are investigated. The combined solid state reaction (CR) produces complex microstructures that exhibit enhanced magnetic hardness (coercivity) relative to the conventionally processed material. The magnetic age hardening response of the CR processed FePd has been reported. For fully equiaxed polycrystalline microstructures of the ordered FePd phase a correlation between the average grain size and the coercivity has been observed. Based on these purely microstructural observations a qualitative coercivity mechanism analysis has been performed in order to elucidate the origin of the decrease in magnetic hardness (coercivity) in the overaged condition.
    Date: 09 June 2004
    Date Type: Completion
    Defense Date: 09 April 2004
    Approval Date: 09 June 2004
    Submission Date: 03 April 2004
    Access Restriction: No restriction; Release the ETD for access worldwide immediately.
    Patent pending: No
    Institution: University of Pittsburgh
    Thesis Type: Master's Thesis
    Refereed: Yes
    Degree: MSMSE - Master of Science in Materials Science and Engineering
    URN: etd-04032004-112438
    Uncontrolled Keywords: annealing; Combined reactions; Electron microscopy; Fe-Pd; ferromagnetic materials; L1sub0 intermetallics; magnetic properties; Thermomechanical processing
    Schools and Programs: Swanson School of Engineering > Materials Science and Engineering
    Date Deposited: 10 Nov 2011 14:33
    Last Modified: 13 Apr 2012 10:59
    Other ID: http://etd.library.pitt.edu/ETD/available/etd-04032004-112438/, etd-04032004-112438

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