Schematic of the HIPPO neutron diffractometer with top hat (yellow, color online) inserted into the HIPPO chamber (blue) surrounded by six detector rings (red).
Top view of HIPPO showing shadowing of detector banks at 120° on top and 60° on bottom from load frame. The total length from the 145° back-scattering detectors to the 40° detectors is 2.2 m, the diameter of the back-scattering detectors is 1.85 m.
Section view of HIPPO from side, illustrating intersection of neutron beam with sample.
Section view of sample environment top hat showing vacuum sealing top plate (dark blue), load frame (purple), rotation stages (grey), quartz push rods (green), vanadium heat shields (orange), heating element (red), and sample (light blue). Overall height is 1.3 m.
Schematic of furnace core with Al2O3 electrical isolators shown in white. Top left: Photograph of half of one shield assembly.
Texture of α-phase (left column) and β-phase (right column) of Zr-2.5Nb at room temperature measured with the sample changer (a) before and (f) after heating and 20% strain in the axial direction, which is the original extrusion direction shown about the center. The radial direction is horizontal and the hoop direction vertical. Revelation of critical factors influencing this material's texture is provided by in situ measurements (b) through (e) using the presented creep furnace. Pre and post treatment conditions of the sample are confirmed in (a/b) and (e/f), respectively. The Burger orientation relationship determines the transition of (0002)hcp/α to maxima in (110)bcc/β during a temperature increase to 975 °C. The resulting textures at high temperature are shown in (c). The (222)bcc/β planes align with the applied compression direction (d).
Relative changes of lattice parameter for a-axis (bottom) and c-axis (top) of α Zr given in Table I. The experimental results of Zr-2.5Nb from this work are in good agreement with Fong et al. 31 and literature values for pure Zr.30
Lattice parameters and volume fractions of both phases as a function of temperature and uni-axial stress are tabulated.
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