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Title:An ultrasonic study of trapped hydrogen in niobium
Author(s):Huang, Kai-Feng
Doctoral Committee Chair(s):Granato, A.V.
Department / Program:Physics
Subject(s):trapped hydrogen
interstitial oxygen
BCC metals
Abstract:The purpose of the present work is to establish a model for the configuration of hydrogen trapped at interstitial oxygen or nitrogen impurities in BCC metals. Such a model would 'be important for an understanding of the physical properties of such systems, particularly of the quantum diffusion effects which occur. A review of all the available data (specific heat, internal friction, neutron scattering, channeling, thermal conductivity) on Nb-O-H or Nb-N-H systems, is first given. By reexamining the data for clues, an eight-state tunnelling model is proposed, and the properties of the system are developed. A comparison of the predictions of this model with the data is given, and the four parameters that describe the model are determined. A simple potential calculation is also performed to demonstrate the qualitative features of the model. Measurements have been made of ultrasonic attenuation and velocity in the Nb-O-H system as a function of temperature, frequency, polarization and isotope. In addition to the previously found stable peak, an additional peak is found when the specimen is cooled rapidly. The peak anneals at the same temperature as those found by Hanada in their resistivity quenching experiments, indicating that the quenched-in defect is an OH2 complex. An extension of the model described in Part A is given to account for the relaxation.
Issue Date:1982
Genre:Dissertation / Thesis
Rights Information:1982 Kai-Feng Huang
Date Available in IDEALS:2011-06-13
Identifier in Online Catalog:18290

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