Non-equilibrium intergranular segregation and embrittlement in neutron-irradiated ferritic alloys

J. Kameda; Y. Nishiyama; T. E. Bloomer

doi:10.1002/sia.1080

Non-equilibrium intergranular segregation and embrittlement in neutron-irradiated ferritic alloys

Surface and Interface Analysis ◽

10.1002/sia.1080 ◽

2001 ◽

Vol 31 (7) ◽

pp. 522-531 ◽

Cited By ~ 10

Author(s):

J. Kameda ◽

Y. Nishiyama ◽

T. E. Bloomer

Keyword(s):

Ferritic Alloys ◽

Non Equilibrium

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Effect of Bulk Phosphorus Content on Hardening, Non-Equilibrium Segregation and Embrittlement in Neutron Irradiated Iron-Based Alloys

MRS Proceedings ◽

10.1557/proc-650-r6.10 ◽

2000 ◽

Vol 650 ◽

Cited By ~ 1

Author(s):

Y. Nishiyama ◽

T. E. Bloomer ◽

J. Kameda

Keyword(s):

Neutron Irradiation ◽

Thermal Aging ◽

Irradiation Effect ◽

Ferritic Alloys ◽

Heat Treated ◽

Ductile Brittle Transition Temperature ◽

P Content ◽

High Bulk ◽

Mn Doped ◽

Non Equilibrium

ABSTRACTThe effect of bulk P contents on hardening, non-equilibrium intergranular segregation and embrittlement has been studied in Mn-doped ferritic alloys subjected to neutron irradiation (E>0.1MeV: fluence of 1 × 1025 n/m2 at 711K for 2120 h) or irradiation-equivalent thermal aging. Neutron irradiation-induced intergranular P segregation became more prominent with decreasing bulk P content. Thermal aging slightly enhanced the amount of segregated P independent of the bulk P content. Intergranular C segregation in all the alloys was suppressed by the irradiation. An alloy with low bulk P content showed only moderate irradiation-induced hardening. The ductile-brittle transition temperature (DBTT) in alloys with low and intermediate amounts of P increased by the same shift during the irradiation but not at all during the thermal aging. Doping high bulk P led to a high DBTT in the as-heat-treated alloy while the irradiation decreased the DBTT. The irradiation effect on the DBTT in the model ferritic alloys containing the different levels of P is discussed in light of embrittling or toughening effects caused by the changes in the P or C segregation, and hardness.

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Application of analytical electron microscopy to studies of equilibrium and non-equilibrium segregation in materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130705 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1214-1215

Author(s):

Edward A Kenik

Keyword(s):

Electron Microscopy ◽

Analytical Electron Microscopy ◽

Extended Defects ◽

Probe Diameter ◽

Specimen Holder ◽

Analytical Electron ◽

Scanning Transmission ◽

Solute Atoms ◽

Equilibrium Segregation ◽

Non Equilibrium

Segregation of solute atoms to grain boundaries, dislocations, and other extended defects can occur under thermal equilibrium or non-equilibrium conditions, such as quenching, irradiation, or precipitation. Generally, equilibrium segregation is narrow (near monolayer coverage at planar defects), whereas non-equilibrium segregation exhibits profiles of larger spatial extent, associated with diffusion of point defects or solute atoms. Analytical electron microscopy provides tools both to measure the segregation and to characterize the defect at which the segregation occurs. This is especially true of instruments that can achieve fine (<2 nm width), high current probes and as such, provide high spatial resolution analysis and characterization capability. Analysis was performed in a Philips EM400T/FEG operated in the scanning transmission mode with a probe diameter of <2 nm (FWTM). The instrument is equipped with EDAX 9100/70 energy dispersive X-ray spectrometry (EDXS) and Gatan 666 parallel detection electron energy loss spectrometry (PEELS) systems. A double-tilt, liquid-nitrogen-cooled specimen holder was employed for microanalysis in order to minimize contamination under the focussed spot.

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