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Experimental characterization of stress corrosion cracking sensitization in austenitic stainless steel using nonlinear ultrasonic Rayleigh waves

This thesis examines the use of nonlinear ultrasound to evaluate sensitization, a precursor to stress corrosion cracking in austenitic stainless steel. Ultrasonic Rayleigh surface waves are generated on a specimen; as these waves pass through sensitized material, second harmonic generation (SHG) increases. In austenitic stainless steel with oven-induced sensitization, this increase is due only to the formation of chromium carbide precipitates, key products of the sensitization process. Weld-induced sensitization specimens demonstrate additional increases in SHG, likely caused by increased residual stress and dislocation density as a result of uneven heating. Experimental data are used to calculate the acoustic nonlinearity parameter, which provides a single value directly related to the quantity of micro- and nano-scale damage present within any given sample. Using this procedure, the effects of weld- and oven-induced sensitization are compared. Results demonstrate the feasibility of using nonlinear Rayleigh waves to detect and monitor stress corrosion susceptibility of welded material.

Identiferoai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/54476
Date07 January 2016
CreatorsLakocy, Alexander J.
ContributorsJacobs, Laurence J.
PublisherGeorgia Institute of Technology
Source SetsGeorgia Tech Electronic Thesis and Dissertation Archive
Languageen_US
Detected LanguageEnglish
TypeThesis
Formatapplication/pdf

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