Electrical Resistance Studies of Hydrogen Diffusion and of Hydride Precipitation in Niobium

Diffusion of hydrogen in niobium was studied by using thermotransport to establish a concentration gradient in a periodic width modulated sample. A sensitive Kelvin double bridge allowed the kinetics of return to uniform concentration to be monitored. In undeformed Nb, the Arhennius plot exhibited a curvature, in agreement with previous results. Deformation indiced by hydride precipitation and by cold work removed the curvature, and increased the fitted values of Do and Q in D = D(,o)e('-Q/kT). These effects are considered to be due to dislocation trapping of H. The undeformed data were fit to the Flynn-Stoneham quantum tunneling model of diffusion. The value for the lattice Debye temperature found was unphysically high (900 K); the validity of the model is therefore in question.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Metallurgical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Clark, Elliot Andrew

• Engineering, Metallurgy

Identifier

(UMI)AAI8701464

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71837