Point defects in NiAl near the equiatomic composition |
| |
Authors: | Jiawen Fan Gary S Collins |
| |
Institution: | (1) Department of Physics, Washington State University, 99164-2814 Pallman, Washington, USA |
| |
Abstract: | Perturbed γ-γ angular correlation spectroscopy was applied to study the structure and properties of point defects near111In probes in quenched and annealed NiAl samples with five compositions in the range cNi=48–52%. Quadrupole interaction signals are analysed in terms of near-neighbor Ni-vacancy and nextnear-neighbor Ni antisite
atom defects. Large mono- and divacancy concentrations were observed in all samples after quenching. For cNi<50%, the vacancy defects could not be annealed out (structural defects). For CNi>50%, large quenched-in vacancy concentrations annealed out near 500°C. For cNi=50%, most vacancies annealed out near 500°C, but about 35% of the111In probes retained a trapped monovacancy. This is attributed to a very low value of the formation enthalpy of a vacancy next
to the In probe, estimated to be 0.16(2) eV. A lesser annelaing stage detected at 300°C is tentatively attributed to diffusion
of Al-vacancies. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|