Assessment of the anisotropic flow stress and plastic strain of Zr–2.5%Nb pressure tubes at temperature from 25 °C to 300 °C

In this paper uniaxial compression testing is used to assess the stress versus plastic strain response in the axial, radial and transverse directions of the mechanically anisotropic Zr–2.5%Nb CANDU pressure tube material over the temperature range from 25 to 300 °C. The data from these tests are used to determine the Hill’s anisotropy coefficients F = 0.38 ± 0.01, G = 0.202 ± 0.001, and H = 0.62 ± 0.01 of the pressure tube material. These coefficients were found to be independent of temperature and plastic strain. The results of this study represent the only experimentation-based determination of the Hill’s anisotropy coefficients F, G, and H of extruded and cold-drawn Zr–2.5%Nb CANDU pressure tubes over a wide temperature range extending up to the 300 °C in-service temperature of these pressure tubes.