Effect of ion irradiation and indentation depth on the kinetics of deformation during micro-indentation of Zr–2.5%Nb pressure tube material at 25°C

Deducing the stress–strain response of anisotropic Zr–2.5%Nb pressure tubing by spherical indentation testing

“…for a given value of h, when the indentation is made on the TN plane compared to the RN or AN planes of the pressure tube. This is consistent with the known mechanical anisotropy of the extruded and cold-drawn Zr-2.5%Nb pressure tube material which dictates that the yield stress in the transverse (circumferential) direction is significantly larger than in the axial or the radial directions of the tube [23,24,[27][28][29][30][31][32][33][34].…”

“…The indentation depth dependence of the r avg Àe avg flow curve It has been observed in most metals that the mechanical strength, either the uniaxial flow stress or the indentation hardness, increases with decreasing sample size less than about several micrometers [24,27,[36][37][38][39]. This type of length-scale dependence was reported for Zr-2.5%Nb material by Bose and Klassen [27] who observed that the indentation stress increased significantly for indentation depths less than about 1 lm.…”

“…The tube was fabricated by 11:1 extrusion of an annular billet at 720°C followed by 27% cold-drawing at room temperature and a 24 h stress relief autoclave treatment at 400°C [23][24][25][26][27]. The mechanical properties of this pressure tube have been studied extensively with uniaxial compression tests and with micro-indentation testing [23,24,[27][28][29][30][31][32][33][34]. Cube-shaped samples, with sides of about 4 mm length, were cut from the pressure tube.…”

Effect of Zr+ ion irradiation on the mechanical anisotropy of Zr–2.5%Nb pressure tube material

“…In a previous study we have reported the results of Zr + ion irradiation (as a simulation of neutron irradiation) on both the depth dependence of the indentation stress and the mechanism of micro-indentation creep of Zr-2.5%Nb pressure tube material at 25°C [23]. Since the indentation tests in that study were performed only on the RN plane, the effect of Zr + ion irradiation on the overall anisotropy of the indentation stress and the indentation creep rate was not studied.…”

“…In this study we present results from pyramidal nano-indentation tests performed, at 25°C, on the RN [23], AN, and TN planes of non-irradiated and Zr + ion-irradiated Zr-2.5%Nb pressure tube material. The objective of the experiments is to investigate the effect of Zr + ion irradiation damage on the anisotropy of the flow stress, including the anisotropy of its indentation depth 0022-3115/$ -see front matter Ó 2010 Elsevier B.V. All rights reserved.…”