The variation of subgrain misorientation in aluminum with large steady-state creep strain
By: Michael E. McMahon
Published: 1986
Language: eng
Number of pages: 72
Subjects: Mechanical engineering
Description: High purity aluminum was torsionally deformed to various strains up to 16.33 at a temperature of 644 K in this study. The variation in the dislocation substructure was determined with increasing strain. Recent work revealed that both the subgrain size and density of dislocations not associated with subgrain boundaries remained constant over the range of steady-state strains examined. However, transmission electron microscopy in this work revealed that subgrain boundaries remained constant over the range of steady-state strains examined. However, transmission electron microscopy in this work revealed that subgrain boundaries undergo two types of basic changes during steady-state creep. At the onset of steady-state behavior (epsilon = 0.20) all subgrain boundaries had small misorientations, typically, 0.6. The misorientation across boundaries formed as a result of dislocation accumulation continued to increase well past steady-state up to a strain of about 1.2, where a maximum average value of 1.2 was observed. This suggests that the dislocation spacing in subgrain boundaries is not principally responsible for the creep resistance during five power-law creep. At strains greater than about four, nearly a third of the subgrain boundaries were determined to be high angle boundaries (HAB).
Notes: Thesis advisor(s): M.E. Kassner.

"June 1986."

Available from National Technical Information Service, Springfield, Va.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, 1986.

Includes bibliographical references.

"Approved for public release; distribution is unlimited"--Cover.

Also available online.

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US Navy (USN) author.

c.1 - 219547, c.2 - 219548