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

Daniel C. Harris; Linda F. Johnson

doi:10.1117/12.354640

26 July 1999 Navy mechanical test results from the sapphire statistical characterization and risk reduction program

Daniel C. Harris, Linda F. Johnson

Proceedings Volume 3705, Window and Dome Technologies and Materials VI; (1999) https://doi.org/10.1117/12.354640
Event: AeroSense '99, 1999, Orlando, FL, United States

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.

Citation Download Citation

Daniel C. Harris and Linda F. Johnson "Navy mechanical test results from the sapphire statistical characterization and risk reduction program", Proc. SPIE 3705, Window and Dome Technologies and Materials VI, (26 July 1999); https://doi.org/10.1117/12.354640

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