Anomalous Ultra-Small-Angle X-ray Scattering from Evolving Microstructures During Tensile Creep

Published

October 12, 2021

Author(s)

P R. Jemian, F Lofaj, Gabrielle G. Long, Sheldon M. Wiederhorn

Abstract

Ultra-small-angle X-ray scattering provides quantitative and statistically significant information on the size distribution of electron density inhomogeneities with dimensions between nearly equal to} 100 and nearly equal to} 5 m. All sizes are sampled simultaneously with a single experiment removing the possibility of observational bias. In a complex material such as commercial silicon nitride, where the inhomogeneities are due to populations of intergranular secondary phases and cavities of similar dimensions, the scattering is a composite of the contributions from the individual populations. A single USAXS scan alone is insensitive to overlapping populations of scatterers due to the different contrasts of a complex morphology. Anomalous USAXS (A-USAXS) is an element-specific contrast variation method used to vary the scattering contribution from one of the populations while holding that of the other populations fixed. To follow the size evolution under tensile creep of both the cavities and the Yb disilicate secondary phases, A-USAXS data was measured near the Yb L_III absorption edge. Both cavity and disilicte size distributions were determined as a function of deformation.

Citation

Proceedings of the MRS Symposium

Pub Type

Journals

Keywords

anomalou scattering, creep cavitation, silicon nitride, x-ray scattering

Citation

Jemian, P. , Lofaj, F. , Long, G. and Wiederhorn, S. (2021), Anomalous Ultra-Small-Angle X-ray Scattering from Evolving Microstructures During Tensile Creep, Proceedings of the MRS Symposium (Accessed December 26, 2024)