University of Illinois Urbana-Champaign

Analysis of dislocation pipe diffusion in deformed alpha-phase PdHX using a synthesized QENS approach

Serio, Joseph Anthony

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SERIO-THESIS-2017.pdf

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https://hdl.handle.net/2142/99282

Description

Title
Analysis of dislocation pipe diffusion in deformed alpha-phase PdHX using a synthesized QENS approach
Author(s)
Serio, Joseph Anthony
Issue Date
2017-09-05
Director of Research (if dissertation) or Advisor (if thesis)
Heuser, Brent
Committee Member(s)
Zhang, Yang
Department of Study
Nuclear, Plasma, & Rad Engr
Discipline
Nuclear, Plasma, Radiolgc Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2018-03-13T15:44:39Z
Keyword(s)
  • Dislocation pipe diffusion
  • Hydrogen
  • Palladium
  • QENS
  • neutron scattering
Abstract
Using quasielastic neutron scattering results from multiple spectrometers, material considerations are made for annealed and deformed PdH_x with sufficiently low [H] as to encourage the process of dislocation pipe diffusion (DPD) below a critical temperature. The results of this analysis indicate that the simultaneous comparison of QENS results from instrument with different instrumental resolution and energy transfer window can provide a more comprehensive picture of the diffusive modes seen within a system than using the instruments independently. A method is developed for accurately comparing the dynamic structure factor S_inc(Q,E) data of multiple instruments, using an inverse Fourier transform in order to obtain the intermediate scattering function F_inc(Q,t) for each instrument and simultaneously analyzing the output from three QENS spectrometers. An array of models are approached to describe the combined F_inc(Q,t), with the best description of F_inc(Q,t) for the deformed PdH_x found to be a summed KWW/single exponential fit. The results show that the DPD contribution to the F_inc(Q,t) can be well described using a stretched exponential (KWW) mode, which is qualitatively correlated to the heterogeneity of the diffusive modes expected for the near-core and inner core region of heavily deformed Pd.
Graduation Semester
2017-12
Type of Resource
text
Permalink
http://hdl.handle.net/2142/99282
Copyright and License Information
2017 by Joseph Anthony Serio. All rights reserved.

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