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Neutron Irradiation of Sapphire for Compressive Strengthening; II. Physical Properties



T M. Regan, D C. Harris, D W. Blodgett, K C. Baldwin, J A. Miragliotta, M E. Thomas, M J. Linevsky, J W. Giles, T A. Kennedy, M Fatemi, David R. Black, P D. Lagerl f


Irradiation of sapphire with fast neutrons (0.8-10 MeV) at a fluence of 1022/m2 increases thec-axis compressive strength and the c-plane biaxial flexure strength at 600 C by a factor of 2.5. Both effects are attributed to inhibition of r-plane twin propagation by damage clusters resulting from neutron impact. The a-plane biaxial flexure strength and 4-point flexure strength in the c- and m-directions decrease by 10-23% at 600 C after neutron irradiation. Neutron irradiation had little or no effect on thermal conductivity, infrared absorption, elastic constants, hardness, and fracture toughness. A featureless electron paramagnetic resonance signal at g=2.02 was correlated with the strength increase. A signal associated with a paramagnetic center containing 2 Al nuclei was not correlated with strength. Ultraviolet and visible color centers also were not correlated with strength in that they could be removed by annealing at temperatures that were too low to reverse the compressive strengthening effect of neutron irradiation.
Journal of the American Ceramic Society
Iss. 1


characterization, compressive strength, neutron irradiation, sapphire


Regan, T. , Harris, D. , Blodgett, D. , Baldwin, K. , Miragliotta, J. , Thomas, M. , Linevsky, M. , Giles, J. , Kennedy, T. , Fatemi, M. , Black, D. and Lagerl f, P. (2002), Neutron Irradiation of Sapphire for Compressive Strengthening; II. Physical Properties, Journal of the American Ceramic Society (Accessed April 15, 2024)
Created December 31, 2001, Updated October 12, 2021