Particle size distributions of γ’ phase were obtained for Waspaloy specimens aged at 725°C and 800°C for times ranging from 120 s to approximately 1x106 s through fitting Small Angle Neutron Scattering (SANS) spectra with a volume distribution of spherical precipitates. The average precipitate radius is found to increase progressively with both aging time and temperature. Electrical resistivity measurements for the aged Waspaloy specimens show an initial increase reaching a maximum at short aging times, followed by a decrease in resistivity with increasing aging time after the resistivity peak. The electrical response was modeled utilizing a microstructural model that accounts for conduction electron scattering from both precipitates and solute atoms. The microstructural model shows a good fit to the measured electrical resistivity, indicating its validity for predicting the electrical response in aged Waspaloy. These results suggest that the electrical response due to aging may be used to quantitatively obtain precipitate microstructural information in Waspaloy in a non-destructive fashion. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.
Technical Paper (PDF 770,03 KB)