EBSP measurements of hydrogenated Zircaloy-2 claddings with stress-relieved and recrystallized annealing conditions

Abstract

Precipitation behavior of zirconium hydrides and microscopic texture in three kinds of Zircaloy-2 fuel claddings with stress-relieved and recrystallized annealing conditions have been examined by electron backscattering diffraction patterns (EBSP). The microscopic texture data obtained by EBSP were consistent with the macroscopic X-ray data. The zirconium basal plane was observed to have a more radial texture in the case of the recrystallized tube as compared to the stress-relieved tube, even though both tubes had the same tube reduction path. In the recrystallized tubes, the frequency of precipitation and stable growth sites in inter-granular hydrides were about twice as high as that in intra-granular sites. In the stress-relieved tubes, this value was not calculated because of the almost equivalent sizes of hydrides and smaller zirconium matrix grains. The observation frequency of the habit planes of hydrides, which was statistically derived based on pole figure analysis of EBSP between hydrides and surrounding zirconium matrix grains, decreased in the order (0 0 0 1) α ∥{1 1 1} δ ≫ {1 0 1 ¯ 7} α ∥{1 1 1} δ > {1 0 1 ¯ 1} α ∥{1 1 0} δ .