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Proceedings Paper

Navy mechanical test results from the sapphire statistical characterization and risk reduction program
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Paper Abstract

The 4-point flexure strength of sapphire in two different crystal orientations was measured between 227 and 600 degrees C. Two types of coupons were fabricated in a manner intended to mimic the way a hemisphere dome would be made. Bar 1 fails in tension at low temperature and from c-axis compression at elevated temperature. Bar 2 fails in tension at all temperatures. As-polished Bar 1 and Bar 2 in the present work ar only about half as strong as comparable bars from previous work. Annealing increased the strength of Bar 2 by 50 percent at all temperature and Bar 1 by 25 percent at low temperature. Annealing did not strengthen Bar 1 at 600 degrees C, at which temperature it fails in compression. A compressive coating had little effect on the strength of annealed bars.

Paper Details

Date Published: 26 July 1999
PDF: 7 pages
Proc. SPIE 3705, Window and Dome Technologies and Materials VI, (26 July 1999);
Show Author Affiliations
Daniel C. Harris, Naval Air Warfare Ctr. (United States)
Linda F. Johnson, Naval Air Warfare Ctr. (United States)

Published in SPIE Proceedings Vol. 3705:
Window and Dome Technologies and Materials VI
Randal W. Tustison, Editor(s)

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