The Effect of Testing Direction on DHC Growth Rate Using Zr-2.5Nb Plate

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Hanlon, Sean




Delayed Hydride Cracking (DHC) is a fracture mechanism responsible for several failures of Zr-2.5Nb CANDU pressure tubes. The crack velocity is directionally dependant. Disk-shaped hydrides preferentially form on certain crystallographic planes that are hypothesized to be responsible for the difference in DHC growth rates. If bulk hydrides slow crack growth, no directional difference in crack velocity will be observed when no bulk hydrides are present. When bulk hydrides are present the crack velocities should begin to diverge as temperature is decreased. In this study, DHC crack velocities
are determined using cantilever beam specimens with cracks propagating in both the longitudinal and through-thickness directions with and without bulk hydrides present, i.e., below and above TSSP. The DHC crack velocities in the longitudinal direction were observed to be higher than the corresponding through-thickness crack velocities with or without bulk hydrides present. Thus, the bulk hydride hypothesis is disproved. Alternative hypotheses are presented.


PHYSICAL SCIENCES Engineering - Materials Science
PHYSICAL SCIENCES Engineering - Nuclear
PHYSICAL SCIENCES Engineering - Mechanical




Carleton University

Thesis Degree Name: 

Master of Applied Science: 

Thesis Degree Level: 


Thesis Degree Discipline: 

Materials Engineering

Parent Collection: 

Theses and Dissertations

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