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Search Publications by: David R Black (Fed)

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Displaying 51 - 56 of 56

Neutron Irradiation to Increase the C-Axis Compressive Strength of Sapphire at Elevated Temperature

February 29, 2000
Author(s)
T M. Regan, D C. Harris, D W. Blodgett, K C. Baldwin, J A. Miragliotta, M E. Thomas, M J. Linevsky, J W. Giles, R M. Stroud, T A. Kennedy, M Fatemi, David R. Black
Neutron irradiation of sapphire with 1 x 10 18 neutrons (≥ 1 MeV)/cm 2 increases the c-axis compressive strength by a factor of 3 at 600 C. The mechanism of strength enhancement is the retardation of r-plane twin propagation by radiation-induced defects

X-Ray Topography Study of Surface Damage in Single-Crystal Sapphire

February 9, 2000
Author(s)
David R. Black, Robert S. Polvani, Kate Medicus, H E. Burdette
X-ray diffraction topography was used to investigate the relationship between sub-surface damage, near-surface microstructure, and fracture strength in a series of sapphire modulus of rupture (MOR) bars which had been fabricated to proof test fabrication

Just How Perfect Can a Perfect Crystal Be?

June 1, 1999
Author(s)
R Deslattes, Ernest G. Kessler, S M. Owens, David R. Black, Albert Henins
This overview addresses certain aspects of the perfection of the current generation of commercially manufactured silicon, specifically lattice uniformity and the more complex issues of interstitials, vacancies, and chemical impurities. The application

X-Ray Diffraction Topography of Sapphire for Windows and Domes

March 30, 1998
Author(s)
David R. Black
X-ray diffraction topography has been used as a nondestructive characterization tool to investigate single-crystal sapphire for window and dome applications. A variety of examples are shown that demonstrate the utility of x-ray diffraction imaging as a