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ETD Abstract Container

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A novel seeding methodology for determining the detectability and effects of inclusions in titanium castings

Ret, Paul Louis
http://rave.ohiolink.edu/etdc/view?acc_num=osu1077548082

Abstract Details

2004, Doctor of Philosophy, Ohio State University, Industrial and Systems Engineering.
A novel artificial inclusion seeding methodology was developed to simulate actual titanium investment casting inclusions. Inclusions were added to machined holes in cast titanium plate (Ti-6Al-4V). After being welded closed in a vacuum, hot isostatic pressing (HIP) was utilized to incorporate the inclusions into the cast material. To validate that this methodology did not result in inherent mechanical property degradation, machined, backfilled, and HIPed holes were produced and compared to virgin, cast Ti-6AL-4V material. Fatigue test results indicated that the drill and HIP methodology did not result in any fundamental mechanical property degradation that would bias comparative results. Validation that the artificially seeded inclusions were equivalent to “as cast” inclusions was completed. The nondestructive inspection response (to multiple techniques), mechanical fatigue behavior, and metallographic characteristics of the inclusions artificially seeded by the developed methodology were determined to be indecipherable from “as cast” inclusions. The industry need for supporting data in terms of nondestructive inspection, metallography, and fatigue life was also addressed by this work. The data generated to evaluate the novel seeding methodology was examined with respect to Ti-6Al-4V casting design and inspection needs. The industry methodology for developing radiographic probability of detection data for both ceramic and hard alpha inclusions was determined to be unconservative. The absence of a reaction zone surrounding inclusions placed on varying thicknesses of material prior to radiographic inspection resulted in an overestimation of what is detectable during manufacturing inspections. Metallographic and mechanical data indicate that of the fatigue life effects of the diffusion zone surrounding hard alpha inclusions are minor compared to the effects of the inclusions themselves. Modeling hard alpha inclusions as sharp penny cracks accounting for a “fixed” diffusion related halo appears appropriate. Nondestructive inspection results indicated that immersion ultrasonics is superior at detecting hard alpha inclusions to X-ray radiography. Limited phased array ultrasonic evaluation identified this technique to present an even better detection potential. However, the inspection method should always be determined based upon the geometry of the component to be inspected and the inclusion size that is required to be found.
Jerald Brevick (Advisor)
323 p.
titanium; casting; inclusion; hard alpha; fatigue

Recommended Citations

Citations

  • Ret, P. L. (2004). A novel seeding methodology for determining the detectability and effects of inclusions in titanium castings [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1077548082

    APA Style (7th edition)

  • Ret, Paul. A novel seeding methodology for determining the detectability and effects of inclusions in titanium castings. 2004. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1077548082.

    MLA Style (8th edition)

  • Ret, Paul. "A novel seeding methodology for determining the detectability and effects of inclusions in titanium castings." Doctoral dissertation, Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1077548082

    Chicago Manual of Style (17th edition)

osu1077548082
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© 2004, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.