Influência do processamento na textura cristalográfica de ligas de Zr-Nb-Mn para aplicação nuclear

Abstract

Zirconium alloys are used in the manufacture of fuel rods due to their low neutron absorption, mechanical properties and good corrosion resistance. The fuel rods integrate the fuel element of nuclear reactors, and during its processing the crystallographic texture on this material is developed. In this context, it is necessary to study the influence of thermomechanical processing on the texture of new alloys for nuclear application. The aim of this work is to study the influence of the addition of Mn, in new alloys based on Zr-Nb, on the development of the crystallographic texture along the adopted processing route, which basically consists of hot rolling, cold rolling and annealing. During operation, the rods can absorb hydrogen and precipitate hydrides, a deleterious phase for this component. The orientation of the hydrides has a strong relationship with texture and ideally it is necessary that the basal planes are parallel to the surface of the tube promoting hydrides in the circumferential direction. After analysis by XRD, it was verified that the Zr-0.9Nb-0.1Mn alloy is the most promising because it presents a more intense basal texture where the basal poles are oriented parallel to the sheet surface. The texture of the alloy composition Zr-0.8Nb-0.2Mn is more random compared to the composition with lower Mn content in which components distant from the basal fiber are strengthened. The Zr-0.6Nb-0.4Mn alloy has the lowest basal fiber intensity among the three studied compositions. Thus, it was possible to infer that the addition of Mn reduces the preferential orientation of the basal poles oriented parallel to the normal direction of the sheet.