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FEASIBILITY STUDY OF THERMAL-ELASTOGRAPHIC DETECTION OF NON-VOIDED HARD-ALPHA INCLUSIONS IN TITANIUM ALLOYS

KRAMER, KEVIN ALBERT
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100552079

Abstract Details

2004, MS, University of Cincinnati, Engineering : Engineering Mechanics.
Hard-alpha inclusions are low-density, hard, brittle regions of spuriously high nitrogen and oxygen content that occur in titanium alloys. Usually, these inclusions are cracked or include voids, so they are easy to detect by ultrasonic means. The difficulty for ultrasonic NDT is detecting the uncracked hard alpha inclusions. This problem is very critical to research since titanium alloys are used in aircraft engines and the material is made more brittle and subject to failure with the added nitrogen and oxygen content. The purpose of this research is to study the feasibility of novel ultrasonic methods to identify nitrogen-enriched regions in titanium alloy components. The three methods studied in this project include thermal expansion, acousto-elastic, and acousto-thermal tests. Our nondestructive measurements provide information on the relevant physical properties of specimens without excess nitrogen content and ones with nitrogen levels ranging from 2.5% - 5.9%. Based on our measurements, the direct thermal expansion effect and the thermally induced acousto-elastic effect are all but negligible relative to the acousto-thermal velocity change. The longitudinal and shear acousto-thermal coefficients were found to be rather sensitive to changes in nitrogen content. Both the longitudinal and shear acousto-thermal coefficients are negative, i.e., the velocities decrease at increasing temperatures. According to our results, the longitudinal coefficient decreases while the shear coefficient increases with increasing nitrogen content. Hopefully, these results can help identify an ultrasonic test method that can detect material inclusions with a level of nitrogen that could be detrimental to an aircraft engine.
Dr. Peter Nagy (Advisor)
71 p.
Engineering, Aerospace
elastography; non-voided hard-alpha inclusions; ultrasonic detection;

Recommended Citations

Citations

  • KRAMER, K. A. (2004). FEASIBILITY STUDY OF THERMAL-ELASTOGRAPHIC DETECTION OF NON-VOIDED HARD-ALPHA INCLUSIONS IN TITANIUM ALLOYS [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100552079

    APA Style (7th edition)

  • KRAMER, KEVIN. FEASIBILITY STUDY OF THERMAL-ELASTOGRAPHIC DETECTION OF NON-VOIDED HARD-ALPHA INCLUSIONS IN TITANIUM ALLOYS. 2004. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100552079.

    MLA Style (8th edition)

  • KRAMER, KEVIN. "FEASIBILITY STUDY OF THERMAL-ELASTOGRAPHIC DETECTION OF NON-VOIDED HARD-ALPHA INCLUSIONS IN TITANIUM ALLOYS." Master's thesis, University of Cincinnati, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100552079

    Chicago Manual of Style (17th edition)

ucin1100552079
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© 2004, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.