TY - JOUR
T1 - An in situ USAXS-SAXS-WAXS study of precipitate size distribution evolution in a model Ni-based alloy
AU - Andrews, Ross N.
AU - Serio, Joseph
AU - Muralidharan, Govindarajan
AU - Ilavsky, Jan
N1 - Publisher Copyright:
© Ross N. Andrews et al. 2017.
PY - 2017/6
Y1 - 2017/6
N2 - Intermetallic γ′ precipitates typically strengthen nickel-based superalloys. The shape, size and spatial distribution of strengthening precipitates critically influence alloy strength, while their temporal evolution characteristics determine the high-temperature alloy stability. Combined ultra-small-, small- and wide-angle X-ray scattering (USAXS-SAXS-WAXS) analysis can be used to evaluate the temporal evolution of an alloy's precipitate size distribution (PSD) and phase structure during in situ heat treatment. Analysis of PSDs from USAXS-SAXS data employs either least-squares fitting of a preordained PSD model or a maximum entropy (MaxEnt) approach, the latter avoiding a priori definition of a functional form of the PSD. However, strong low-q scattering from grain boundaries and/or structure factor effects inhibit MaxEnt analysis of typical alloys. This work describes the extension of Bayesian-MaxEnt analysis methods to data exhibiting structure factor effects and low-q power law slopes and demonstrates their use in an in situ study of precipitate size evolution during heat treatment of a model Ni-Al-Si alloy.Combined ultra-small-, small- and wide-angle X-ray scattering (USAXS-SAXS-WAXS) provides in situ evaluation of the precipitate size distribution (PSD) and phase structure temporal evolution during heat treatment. A method for extraction of an arbitrary PSD in the presence of interparticle interactions is described and illustrated for study of PSD evolution.
AB - Intermetallic γ′ precipitates typically strengthen nickel-based superalloys. The shape, size and spatial distribution of strengthening precipitates critically influence alloy strength, while their temporal evolution characteristics determine the high-temperature alloy stability. Combined ultra-small-, small- and wide-angle X-ray scattering (USAXS-SAXS-WAXS) analysis can be used to evaluate the temporal evolution of an alloy's precipitate size distribution (PSD) and phase structure during in situ heat treatment. Analysis of PSDs from USAXS-SAXS data employs either least-squares fitting of a preordained PSD model or a maximum entropy (MaxEnt) approach, the latter avoiding a priori definition of a functional form of the PSD. However, strong low-q scattering from grain boundaries and/or structure factor effects inhibit MaxEnt analysis of typical alloys. This work describes the extension of Bayesian-MaxEnt analysis methods to data exhibiting structure factor effects and low-q power law slopes and demonstrates their use in an in situ study of precipitate size evolution during heat treatment of a model Ni-Al-Si alloy.Combined ultra-small-, small- and wide-angle X-ray scattering (USAXS-SAXS-WAXS) provides in situ evaluation of the precipitate size distribution (PSD) and phase structure temporal evolution during heat treatment. A method for extraction of an arbitrary PSD in the presence of interparticle interactions is described and illustrated for study of PSD evolution.
KW - Bayesian inverse transformation
KW - USAXS-SAXS-WAXS
KW - precipitation hardening
KW - small-angle X-ray scattering
KW - ultra-small-angle X-ray scattering
KW - wide-angle X-ray scattering
UR - http://www.scopus.com/inward/record.url?scp=85020181170&partnerID=8YFLogxK
U2 - 10.1107/S1600576717006446
DO - 10.1107/S1600576717006446
M3 - Article
AN - SCOPUS:85020181170
SN - 0021-8898
VL - 50
SP - 734
EP - 740
JO - Journal of Applied Crystallography
JF - Journal of Applied Crystallography
IS - 3
ER -