NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Sapphire Statistical Characterization and Risk Reduction Program
Published
Author(s)
Donald McClure, Robert Cayse, David R. Black, Steven Goodrich, K Lagerloef, D Peter, Daniel C. Harris, Dale McCullum, Daniel H. Platus, Charles E. Patty, Robert S. Polvani
Abstract
The Sapphire Statistical Characterization and Risk Reduction Program tested 1400 4-point flexure bars with different crystal orientations at different temperatures to establish a mechanical strength database for engineering design. Sapphire coupons were selected to represent surfaces on two different missile windows and a missile dome. Sapphire was obtained from the same suppliers used for the windows or dome and, as much as possible, coupons were fabricated in the same manner as the corresponding part of the window or dome. For one missile window, sapphire from one fabricator was 50% stronger than sapphire made to the same specifications from the same blanks by another fabricator. In laser thermal shock tests, sapphire performed better than predicted from flexure tests. Of several nondestructive methods evaluated for their ability to identify mechanically weak specimens, only x-ray topography was correlated with strength for a limited set of specimens.
McClure, D.
, Cayse, R.
, Black, D.
, Goodrich, S.
, Lagerloef, K.
, Peter, D.
, Harris, D.
, McCullum, D.
, Platus, D.
, Patty, C.
and Polvani, R.
(2001),
Sapphire Statistical Characterization and Risk Reduction Program, Intl Society for Optical Engrg (SPIE), Orlando, FL
(Accessed October 15, 2025)