INVESTIGADORES
CASTELLANO Gustavo Eugenio
artículos
Título:
EBSD spatial resolution for detecting sigma phase in steels
Autor/es:
S. FERNANDEZ BORDÍN; S. LIMANDRI; J.M. RANALLI; G. CASTELLANO
Revista:
ULTRAMICROSCOPY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2016 vol. 171C p. 177 - 185
ISSN:
0304-3991
Resumen:
The spatial resolution of the electron backscatter diffraction signal is explored by Monte Carlo simulation for the sigma phase in steel at atypical instrumental set-up. In order to estimate the active volume corresponding to the diffracted electrons, the fraction of the backscattered electrons contributing to the diffraction signal was inferred by extrapolating the Kikuchi pattern contrast measured by other authors, as a function of the diffracted electron energy. In the resulting estimation, the contribution of the intrinsic incident beam size and the software capability to deconvolve patterns were included.A strong influence of the beam size on the lateral resolution was observed, resulting in 20 nm for the aperture considered. For longitudinal and depth directions the resolutions obtained were75 nm and 16 nm, respectively. The reliability of this last result is discussed in terms of the survey of the last large-angle deflection undergone by the backscattered electrons involved in the diffraction process.Bearing in mind the mean transversal resolution found, it was possible to detect small area grains of sigma phase by EBSD measurements, for a stabilized austenitic AISI 347 stainless steel under heat treatments,simulating post welding (40 h at 600 ºC) and aging (284 h at 484 ºC)effects ---as usually occurring in nuclear reactor pressure vessels.