Award Date

1-1-2007

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

First Committee Member

Ajit K. Roy

Number of Pages

145

Abstract

Austenitic Alloy C-22 exhibited reduced failure strain (ef) and serrations under tensile loading within susceptible temperature regimes, indicating the occurrence of dynamic-strain-aging (DSA) phenomenon. A maximum dislocation density was observed at 600°C at which the lowest ef was noted. An average activation energy of 46 kJ/mole was liable for diffusion of solute elements, causing serrations. A maximum work hardening was observed at the slowest strain rate. A slope of 4.0 was determined from crack-growth testing, satisfying the Paris law. A combination of elevated temperature and acidic pH resulted in enhanced cracking tendency. More noble (positive) applied potential led to greater susceptibility to cracking in the acidic solution. The critical potentials became more active (negative) at higher temperatures. The increased wedge-loads caused greater cracking tendency of double-cantilever-beam (DCB) specimens. C-ring and U-bend specimens did not show any cracking in an acidic solution. The cylindrical specimens, used in tensile and environmental-cracking studies, showed ductile failures.

Keywords

Alloy; Base; Characterization; Corrosion; Crack; Crack Growth; Deformation; Growth; Nickel; Nickel Alloys; Tensile Deformation

Controlled Subject

Materials science; Materials science

File Format

pdf

File Size

4792.32 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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