|About this Abstract
||Materials Science & Technology 2019
||Materials for Nuclear Applications
||Anisotropy in Thermal Creep and Creep Life Prediction of Zr-2.5%Nb Pressure Tube Alloy
||Vivek Laxman Patel, Ram Niwas Singh
|On-Site Speaker (Planned)
||Vivek Laxman Patel
Zr-2.5Nb alloy, with its high yield strength and low hydrogen absorption, is used in PHWR pressure tube. The thermal creep behavior of the Zr-2.5Nb alloy was studied for different temperatures (350-450oC), stresses (0.7YS–0.9YS) and orientations (transverse/longitudinal). A model was proposed to predict the creep life and minimum creep rate of the pressure tube at reactor working conditions (300oC, 10MPa) using the Wilshire Method.
Results showed stress exponents in the range of 4-8, indicating predominantly dislocation creep mechanism. Activation energies of ≈150-200kJ/mol were close to the self-diffusion activation energy for Zr (≈230kJ/mol). Anisotropy developed from inherent texture caused higher creep in longitudinal direction. Above 400oC, activation of additional slip systems enhanced transverse creep. Similar behaviour was also reflected in the tensile tests performed. The predicted creep curves from modelling showed good description of the experimental data.