Strain Determination of An Eutectic Single Crystal Composite Al 2 O 3 /Y 3 Al 5 O l2 (YAG) by Neutron Diffraction Techniques At Reactor and Pulsed Sources

Abstract

Bragg diffraction angle analysis with a high-resolution strain diffractometer and time-of-flight analysis with backscattering powder diffractometer were complementarily applied to neutron residual strain investigations in an ultra-high temperature resistant composite of eutectic two-phase Al₂O₃/Y₃A1₅O₁₂ (YAG) single-crystal. It was found that the YAG phase was in tension and the A1₂O₃ phase was in compression which resulted in strains ε in the range of ∼10⁻⁴ at room temperature, when the measured lattice spacings of the sintered YAG and sintered Al₂O₃ w ere used as the reference values of strain-free materials. Discussions are given on the methodological points of both analyses with respect to evaluation of a strain value for each phase in the two-phase single crystal materials.