Grain boundary segregation in ferromagnetic alloys

Ishida, K.; Yokoyama, S.; Nishizawa, Tsutomu

doi:10.1016/0001-6160(85)90143-9

Cited by 26 publications

(8 citation statements)

References 22 publications

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“…[21][22][23] The influence of the ferromagnetic transition on the segregation of impurities has already been studied experimentally. 24,25 It was found, for example, that in Co-50%Ni alloys the segregation of Sb and S is intensified when the transition to the magnetic state of the alloy is achieved. 25 Very recently, the application of an external magnetic field to control the segregation of impurities to the GBs was proposed.…”

Section: Introductionmentioning

confidence: 99%

“…24,25 It was found, for example, that in Co-50%Ni alloys the segregation of Sb and S is intensified when the transition to the magnetic state of the alloy is achieved. 25 Very recently, the application of an external magnetic field to control the segregation of impurities to the GBs was proposed. 26,27 After a so-called magnetic annealing, the concentration of Sn impurity atoms at the GBs in iron-tin alloys was found to be the same as in the bulk although before the annealing it was 1.5 times higher.…”

Section: Introductionmentioning

confidence: 99%

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First-principles study of magnetism at grain boundaries in iron and nickel

2008

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The geometric and magnetic structures of fully relaxed symmetrical tilt ⌺5͑310͒ grain boundaries ͑GBs͒ in iron and ⌺5͑210͒ GBs in nickel have been investigated using density-functional theory. We found for both GBs an enhancement of the local magnetic moments of atoms in the GB plane ͑2.55 B for iron and 0.67 B for nickel͒ which is correlated with the larger local atomic volume compared to the bulk. At larger distances from the GB the variation of the local magnetic moments follows the changes in the exchange splitting in the spin-polarized local density of states imposed by the local variations in the atomic geometry. When Si and Sn impurity atoms in interstitial or substitutional positions appear at the ⌺5͑310͒ GB in iron, the local magnetic moments of iron atoms are reduced for silicon and almost unchanged for tin. We also calculated the segregation enthalpies of both impurities and confirmed the experimental fact that silicon is a substitutional and tin an interstitial segregant; the calculated values of segregation enthalpy are in good agreement with experiment.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

First-principles study of magnetism at grain boundaries in iron and nickel

2008

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“…22 Generally, the Figure 10. Grain boundary segregation of phosphorus in Ni20%Cr at 650 "C, Auger peak height ratio APIAN, plotted vs. time for alloys with different P (and C) concentrations.…”

Section: Resultsmentioning

confidence: 99%

Contributions of AES in four metallurgical studies

Grabke

1989

Surface & Interface Analysis

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Four recent studies are reported characterizing the possible contributions of surface science to metallurgy. The grain boundary segregation of phosphorus was studied by AES analyses of fractured specimens-after many studies on femtic iron steels-in the austenitic range for Fe-P, Fe-Mn-P, FeC-P and Fe-P-B alloys. Also, in N~2 0 % C r the grain boundary segregation of P and its effects on carbide precipitation were investigated. On surfaces of ternary alloys Fe-M-I, co-segregation of the metal M and ooo-metal element I can lead to the formation of two-dimensional or three-dimensional surface compounds, as demonstrated for the system FeCr-N. The formation of such nitrides in the first transient state of tbe oxidation of high-temperature alloys can strongly deteriorate the protective properties of the chromia layer formed-as shown for the oxidation of Fe-tO%Cr in

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“…However, this transition may also a ect D s indirectly. Indeed, it is known that the segregation of residual impurities at the GBs in Fe increases strongly below T C (Ishida et al 1985). It is very probable that the same e ect occurs also in the case of surface segregation.…”

Section: Energies and Kinetics Of Surfaces And Interfaces In The Fe±pmentioning

confidence: 97%

Energetics and kinetics of surfaces and interfaces in the Fe-Pb system

Monchoux¹,

Gutmanas²,

Rabkin³

2002

Philosophical Magazine Letters

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The energy and the di usivity of interfaces in the solid Fe±liquid Pb system have been investigated in the temperature range 650±900°C. Grain-boundary grooves are formed at the solid Fe±liquid Pb interface and these have been studied by atomic force microscopy. From the topography of the grooves the relative interfacial energies and interfacial di usivities are obtained. It is found that liquid Pb does not wet the grain boundaries in Fe. Possible mechanisms for the growth of the grain-boundary grooves are discussed. } 1. Introduction It has been known for a long time that liquid metals can penetrate along the grain boundaries (GBs) of solid metals, either with or without applied stress, causing a dramatic embrittlement of intrinsically ductile metals (Lynch 1982). This phenomenon is far from being understood. In the case of liquid-metal embrittlement (LME) under stress, some of the ideas of fracture mechanics can be applied (Rabkin 2000). However, the rapid penetration of liquid along the GBs in the absence of stress is more mysterious. Moreover, it is not clear whether, in a given solid±liquid couple, penetration will occur or not, because the mechanisms leading to liquid metal penetration along GBs are still largely unknown.A study of the Fe±Pb system is of special interest for the above reasons. To our knowledge, the GB wetting behaviour of this couple has not been determined unambiguously. Indeed, sessile droplet experiments with molten Pb on an Fe surface (Naidich 1972) showed that a low value for the contact angle at the triple line (which means intimate physical contact) was di cult to obtain, and that this angle was highly dependent on the solid±liquid interfacial chemistry. Naidich demonstrated that, for relatively low temperatures, the contact angle in the Fe±Pb system was atypically large for a metal±metal system, this poor wetting being associated with the presence of a thin oxide ®lm on the surface of Fe and at the Fe±Pb interface. The same kind of di culty would obviously occur in GB wetting experiments. Therefore, the e ects of the solid±liquid interface chemistry have to be properly taken into account. Moreover, the temperature dependence of the Pb solubility in solid Fe is not precisely known (Massalski et al. 1990). This makes the measurement of the true equilibrium wettability more di cult, since it can be established only when the equilibrium concentrations corresponding to the solubility limits both in

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Grain boundary segregation in ferromagnetic alloys

Cited by 26 publications

References 22 publications

First-principles study of magnetism at grain boundaries in iron and nickel

First-principles study of magnetism at grain boundaries in iron and nickel

Contributions of AES in four metallurgical studies

Energetics and kinetics of surfaces and interfaces in the Fe-Pb system

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