X-ray diffraction study of static distortion of the host zirconium lattice in interstial Zr-O solid solutions

Static distortions of the host zirconium lattice as caused by the interstitial oxygen atoms have been determined by X-ray diffraction for Zr-23.6 and 24.8 at. % O alloys. The arrangement of oxygen atoms in the former alloy is specified by the ZrO_x or ABC-type stacking structure and that in the latter by a statistical sequence of two kinds of oxygen layer, i.e. single A and double AB layers. The present work has proved that each zirconium atom shifts toward the adjacent oxygen atoms and the magnitude of the displacement is about 0.04 Å for both the alloys. The anomalous dependence of the lattice constants on oxygen concentration is qualitatively explained by the local contraction in the c plane.