Thermal Creep Behavior of Nanocrystalline Zr-Nb Binary Alloy at High Uniaxial Pressure in Atomic-Scale

Abstract

Zirconium (Zr) alloys with niobium are as an important structural material such as clad tubes, that are subjected to high-temperatures, pressures, and irradiation flux and their mechanical properties which can be changed in this process. In this study, the tensile creep behavior of these alloys has been investigated at high temperatures and pressures. The effect of grain size (GS) on the creep behavior of Zr-1%Nb alloy under different pressures and temperatures has been monitored using molecular dynamics approach. Accordingly, the deformation rate for the different creep stages (initial, steady-state, and tertiary stages) which is due to the production and diffusion of defects, has been explored. It has been shown that at high temperatures, the deformation rate of this alloy generally decreases with increasing GS. Furthermore, increasing the temperature and pressure results in a greater creep rate. Radial distribution function (RDF) and mean square displacement (MSD) have also been calculated for these cases to provide deeper insight into the creep behavior under tough condition.

Keywords

• zr-1%nb alloy
• molecular dynamics
• creep behavior
• grain size
• high-temperature