Microstructure and texture analysis of δ-hydride precipitation in Zircaloy-4 materials by electron microscopy and neutron diffraction

WANG, ZHIYANG; GARBE, ULF; LI, HUIJUN; WANG, YANBO; STUDER, ANDREW J.; SUN, GUANGAI; HARRISON, ROBERT P.; LIAO, XIAOZHOU; VICENTE ALVAREZ, M.A.; SANTISTEBAN, J.R.; KONG, CHARLIE

JOURNAL OF APPLIED CRYSTALLOGRAPHY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2014 vol. 47 p. 303 - 315

0021-8898

This work presents a detailed microstructure and texture study of various hydrided Zircaloy-4 materials by neutron diffraction and microscopy. The results show that the precipitated δ-ZrH1.66 generally follows the δ(111)//α(0001) and δ[ ]//α[ ] orientation relationship with the α-Zr matrix. The δ-hydride displays a weak texture that is determined by the texture of the α-Zr matrix, and this dependence essentially originates from the observed orientation correlation between α-Zr and δ-hydride. Neutron diffraction line profile analysis and high-resolution transmission electron microscopy observations reveal a significant number of dislocations present in the δ-hydride, with an estimated average density one order of magnitude higher than that in the α-Zr matrix, which contributes to the accommodation of the substantial misfit strains associated with hydride precipitation in the α-Zr matrix. The present observations provide an insight into the behaviour of δ-hydride precipitation in zirconium alloys and may help with understanding the induced embrittling effect of hydrides. © 2014 International Union of Crystallography.