Characterisation of β-quenched and thermally aged Zircaloy-2 by positron annihilation, hardness and ultrasonic velocity measurements

Grain fragmentation and twinning in deformed Zircaloy 2: Response to positron lifetime measurements

“…PAS, especially PAS lifetimes, has been used effectively in the past [14][15][16][17][18][19][20][21][22]; but rarely such efforts were coordinated or coupled with other defect characterization techniques and tools. The deformed Zircaloy 2, material of the present study, has two interesting features: fragmenting/non-fragmenting grains [24] and deformation twinning [23].…”

“…A positron source was prepared by 22 Na in the form of NaCl deposited in Kapton foil [16]. This was placed between two pieces of Zircaloy 2 samples so that all emitted positrons enter the sample.…”

“…With this set-up, the time delay between the 1280 keV ␥-ray accompanying positron emission by 22 Na and the subsequent 511 keV annihilation radiation were measured. The instrumental time resolution and source correction terms were obtained from the measured spectrum of silicon, a medium of known PAS lifetime, using a computer program Resolution [25].…”

“…For example, X-ray line profile analysis, ranging from simple Williamson-Hall estimates of lattice strain [6][7][8] to more elegant micro-stress or dislocation density [2,[9][10][11][12][13] measurements, depends on the availability of proper diffraction peaks and are sensitive only to dislocations. Positron annihilation spectroscopy (PAS) can also be used for indirect dislocation estimates, though its actual niche is in the area of characterizing vacancies and interfaces [14][15][16][17][18][19][20][21][22]. It remains an open-ended question if information available from different analytical techniques, both bulk and micro, can be linked or coupled and this constituted the motivation behind the present study.…”

Characterization of mechanical properties of a hollow cylinder with zero group velocity Lamb modes

“…In nuclear industry, material properties of Zircaloy cladding tubes need to be evaluated to ascertain of their safety and reliability. 1,2 The most popular methods used in nondestructive evaluation (NDE) are radiography, eddy current, and ultrasound techniques. Over the last decades, many NDE ultrasonic methods have been developed.…”