Thermal Annealing of Vacancy and Interstitial Loops in Ion Irradiated Copper

Abstract

X-ray diffuse scattering has been used to study the thermal annealing of vacancy and interstitial loops in Ni-ion irradiated copper. The diffuse scattering formalism is reviewed and diffuse scattering measurements are reported on liquid-He temperature Ni-ion irradiated copper after annealing to 40, 275, and 300 °C. Size distributions are presented for vacancy and interstitial loops after each anneal and the thermal-induced changes are discussed in terms of loop dissolution and coalescence.

Historical Perspective on Diffraction Line-Profile Analyses for Crystals Containing Defect Clusters

“…Subsequent to the calculations for dislocation loops in aluminum [22] and the insight provided by the results contained in Figure 5 of Reference [26], Larson and Young [27] investigated the diffuse scattering implications of the form of the displacement field for loops as a function of r within the close proximity of the loop plane. As can be seen in the loop displacement fields plotted in Figure 4, which represents the work of Ohr [23], there is an inflection point in the loop-normal displacement field for loops.…”

“…Although the asymptotic scattering region is too complicated to be handled analytically in closed form [14], numerical calculations of the scattering from loops can be performed straightforwardly for vacancy (b < 0) and interstitial (b > 0) loops of desired sizes on specified lattice planes using Equation (6) and the displacement field calculations of Ohr [23]. Accordingly, Larson and Young demonstrated, in conference proceedings [27] in 1982 and in a more complete journal paper [28] in 1987, the ability to extract separate size distributions for vacancy and interstitial loops from diffuse scattering measurements. Size distributions were extracted directly by non-linear least-squares fitting of cross-sections for 10-60-Å-radius vacancy and interstitial {111} loops to X-ray diffuse scattering measurements on neutron-irradiated Cu in Reference [27] and on both Ni-ion-irradiated and neutron-irradiated Cu in Reference [28].…”

“…Accordingly, Larson and Young demonstrated, in conference proceedings [27] in 1982 and in a more complete journal paper [28] in 1987, the ability to extract separate size distributions for vacancy and interstitial loops from diffuse scattering measurements. Size distributions were extracted directly by non-linear least-squares fitting of cross-sections for 10-60-Å-radius vacancy and interstitial {111} loops to X-ray diffuse scattering measurements on neutron-irradiated Cu in Reference [27] and on both Ni-ion-irradiated and neutron-irradiated Cu in Reference [28].…”

“…Firstly, to reveal the details of diffuse scattering in the asymptotic region (i.e.,~q −4 intensity falloff), it is useful to scale the scattering cross-sections and the diffuse scattering measurements by q 4 , where q is the radial distance (parallel or anti-parallel) to the reciprocal lattice vector as shown in Figure 5 below. Figure 5 is a composite describing the extraction of vacancy and interstitial loop size distributions from X-ray diffuse scattering measurements as discussed in References [27][28][29]. The measurements were performed near the (222) Bragg reflection on a copper single crystal that was irradiated with high-energy 60-MeV Ni-ions for a previous "integral" diffuse scattering study [30].…”

In situ study of cascade defects in silver by simultaneous transmission electron microscopy and electrical resistivity measurements at low temperatures

“…One of the double-tilt stages is equipped for simultaneous electrical resistivity measurements of TEM specimens and also with a heater to facilitate specimen temperature cycling experiments such as isochronal annealing. Electrical resistivity measurements complement TEM observations by providing information on submicroscopic defects, the existence of which has been indicated by resistivity measurements [9] and x-ray diffuse scattering measurements [10,11].…”