Hydride reorientation in Zr2.5Nb studied by synchrotron X-ray diffraction

• Autores: Vicente Alvarez, Miguel Angel; Santisteban, Javier Roberto; Vizcaino, Pablo; Flores, Alejandra V.; Banchik, Abraham David; Almer, J.
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: texture; Zr-2.5Nb; pressure tubes; hydrides
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The crystallographic texture and stress state of hydride platelets of two different orientations precipitated in Zr2.5Nb pressure tubes were studied by synchrotron X-ray diffraction experiments using an 80 keV photon beam and an area detector in transmission geometry. Circumferential and radial hydrides with platelet normals along the tube radial and circumferential directions, respectively, were precipitated in tube material loaded up to H contents of 130 wt.ppm. This macroscopic hydride orientation was controlled by application of a load along the tube hoop direction during hydride precipitation. The experiments show that both circumferential and radial platelets are composed of delta-hydrides precipitated in alpha-Zr grains from a wide range of orientations, but with a clear preference for Zr crystals with their c-axes at an angle of 15?20 deg from the hoop direction. Some moderate differences between the crystallographic texture of the two hydrides result from application of the load during precipitation. The results are explained in terms of an autocatalytic nucleation process and the Zr2.5Nb microstructure. A careful stress analysis revealed that both hydride types are compressed by the matrix on the plane of the platelet, with the largest stresses always found along the axial direction of the tube. Determination of the stress state of the hydride could be exploited as a diffraction signature of the hydride orientation.Delta-hydrides precipitated in alpha-Zr grains from a wide range of orientations, but with a clear preference for Zr crystals with their c-axes at an angle of 15?20 deg from the hoop direction. Some moderate differences between the crystallographic texture of the two hydrides result from application of the load during precipitation. The results are explained in terms of an autocatalytic nucleation process and the Zr2.5Nb microstructure. A careful stress analysis revealed that both hydride types are compressed by the matrix on the plane of the platelet, with the largest stresses always found along the axial direction of the tube. Determination of the stress state of the hydride could be exploited as a diffraction signature of the hydride orientation.
Fil: Vicente Alvarez, Miguel Angel. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina
Fil: Santisteban, Javier Roberto. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina
Fil: Vizcaino, Pablo. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia Ciclo del Combustible Nuclear. Laboratorio de Materia de la Fábrica de Aleaciones Especiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Flores, Alejandra V.. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia Ciclo del Combustible Nuclear. Laboratorio de Materia de la Fábrica de Aleaciones Especiales; Argentina
Fil: Banchik, Abraham David. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia Ciclo del Combustible Nuclear. Laboratorio de Materia de la Fábrica de Aleaciones Especiales; Argentina
Fil: Almer, J.. No especifíca;