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Title: A phase field model for segregation and precipitation induced by irradiation in alloys

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Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Modelling and Simulation in Materials Science and Engineering
Additional Journal Information:
Journal Volume: 23; Journal Issue: 3; Journal ID: ISSN 0965-0393
IOP Publishing
Country of Publication:
United Kingdom

Citation Formats

Badillo, A., Bellon, P., and Averback, R. S.. A phase field model for segregation and precipitation induced by irradiation in alloys. United Kingdom: N. p., 2015. Web. doi:10.1088/0965-0393/23/3/035008.
Badillo, A., Bellon, P., & Averback, R. S.. A phase field model for segregation and precipitation induced by irradiation in alloys. United Kingdom. doi:10.1088/0965-0393/23/3/035008.
Badillo, A., Bellon, P., and Averback, R. S.. 2015. "A phase field model for segregation and precipitation induced by irradiation in alloys". United Kingdom. doi:10.1088/0965-0393/23/3/035008.
title = {A phase field model for segregation and precipitation induced by irradiation in alloys},
author = {Badillo, A. and Bellon, P. and Averback, R. S.},
abstractNote = {},
doi = {10.1088/0965-0393/23/3/035008},
journal = {Modelling and Simulation in Materials Science and Engineering},
number = 3,
volume = 23,
place = {United Kingdom},
year = 2015,
month = 3

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1088/0965-0393/23/3/035008

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Cited by: 7works
Citation information provided by
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  • A model describing neutron irradiation-induced grain boundary segregation at a given temperature is established for dilute alloys based on a complex diffusion mechanism and combined with McLean`s equilibrium segregation model. In the model, irradiation-enhanced solute diffusion is taken into consideration. The diffusion equations are more rigorously solved than in earlier models, so that an accurate definition of the grain boundary solute concentration is given as a function of time. The effect of the temperature dependence of dislocation density is accommodated and the estimation method for complex diffusion is reappraised. Theoretical predictions are made for segregation of phosphorus in neutron-irradiated {alpha}-Fe.more » There exists a transition temperature below which combined irradiation-induced nonequilibrium and irradiation-enhanced equilibrium segregation is dominant and above which thermal equilibrium segregation is dominant. The peaks in the temperature dependence of segregation shift to lower temperatures with decreasing neutron dose rate and/or increasing neutron dose. The combined radiation-induced nonequilibrium and radiation-enhanced equilibrium peak segregation temperature is about 150 C for P grain boundary segregation in neutron-irradiated {alpha}-Fe at dose rate = 10{sup {minus}6} dpa/s and dose = 1 dpa. The thermal equilibrium segregation peak is around 550 C for the same conditions. Comparison of some experimental and predicted results shows that the predictions are generally consistent with the observations.« less
  • Solute segregation and precipitation in dilute alloys during irradiation have been studied by means of the Johnson--Lam kinetic model. The model is based on a combination of chemical reaction rates and diffusion equations for free defects, solutes, and bound defect-solute complexes. The enrichment of solute at sink surfaces and solute depletion in the matrix have been calculated as functions of temperature, damage rate, defect-solute binding energy, and initial solute concentration. Using parameters appropriate for Be in Ni, significant solute segregation is found in the temperature range from 0.2 to 0.7 T/sub m/. The temperature for maximum segregation is higher formore » the high displacement rates typically used in charged-particle bombardment experiments than for the low displacement rates used in fast-reactor irradiations. The solute concentration at the sink surface builds up at high temperatures, without surpassing the solubility limit, until a steady state is attained. At lower temperatures solute enrichment at sinks becomes larger and the solubility, in general, becomes lower. Precipitation will occur when the local solute concentration reaches that of the phase boundary. The solute concentration at the precipitate-matrix interface is determined by the solubility limit, and precipitation continues until the matrix is sufficiently solute-depleted to achieve a steep concentration gradient that will balance the defect-induced solute flow by back-diffusion. The steady-state matrix composition is determined by radiation conditions and is independent of the initial alloy composition when precipitation occurs. The solute depletion at steady state is more severe at low displacement rates than at high rates. The calculations are qualitatively compared with recent experimental observations of the temperature and compositional dependence of solute precipitation in the Ni--Be system.« less
  • The earlier combined model [Faulkner and Jiang, Mater. Sci. Technol. 9, 665 (1993)] is improved by means of modifying the kinetics of segregation and taking into account the nucleation of grain boundary precipitates, the precipitate growth and coarsening. The newly developed model predicts the influence of the heat treatment on the widths of precipitate-free zones, the growth rate and the dispersion of the precipitates on the grain boundaries during the growth of precipitates. It also predicts the critical time when coarsening begins, the size and dispersion of precipitates on the grain boundaries during coarsening. The application of the model inmore » predicting the size and inter-particle spacing of MgZn{sub 2} grain boundary precipitate and the widths of precipitate-free zones in 7150 aluminium alloy as a function of heat treatment is discussed in Part 1 of this paper, and the comparison of the predicted and experimental results will be addressed in Part 2.« less
  • The studies of irradiation-induced solute segregation (IISS) and irradiation-induced precipitation (IIP) in Ni-Si and Pd-Fe alloys have been completed. Progress is reported for several other projects: irradiation damage in binary Pd-Cr, -Mn and -V alloys (15 at. %); IIP in Pd-Mo and Pd-W alloys; IIP in Pd-25 at. % Cr alloy; and irradiation damage effects in proton-bombarded metallic glasses (Ni-65 Zr, 40 Fe 40 Ni 14 P6B). 27 figures. (DLC)