The ASTM G 67 test is a current technique used in accessing the Degree of Sensitization (DoS) of 5xxx aluminum alloys used for commercial and military purposes in the marine industry. A call has been made by the US Navy for an alternative technique to replace the ASTM G 67 test due to its deficiencies. In this thesis, the Resonance Ultrasound Spectroscopy (RUS) and Pulse-Echo (PE) ultrasonic techniques were used to characterize the DoS in 5083 and 5456 aluminum alloys. Results from the study show that ultrasonic wave attenuation is very sensitive to DoS. Ultrasonic shear wave velocity is less sensitive but still a reliable and consistent marker for sensitization. Ultrasonic longitudinal wave velocity is least sensitive, requiring a very precise measurement to be useful. Furthermore, the results show that DoS grows with thermal treatment faster for 5456 than 5083 aluminum alloys. The overall DoS accumulation (to full saturation) for 5456 is approximately 20% larger than that for 5083. Ultrasonic parameters, especially attenuation, appear to be reliable candidates to non-destructively monitor the DoS in 5xxx aluminum alloys.
|Advisor:||Petculescu, Gabriela L.|
|Commitee:||Hollerman, William A., Petculescu, Andi G.|
|School:||University of Louisiana at Lafayette|
|School Location:||United States -- Louisiana|
|Source:||MAI 53/01M(E), Masters Abstracts International|
|Subjects:||Materials science, Acoustics|
|Keywords:||Aluminum alloys, Sensitization, Ultrasound|
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