First principle study of cobalt impurity in bcc Fe with Cu precipitates

Medvedeva, N. I.; Murthy, Arpana S.; Richards, Von; Aken, David C. Van; Medvedeva, Julia E.

doi:10.1007/s10853-012-6884-2

Cited by 18 publications

(9 citation statements)

References 74 publications

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“…Some uncertainty in the elastic interaction part may come from the size-mismatch. According to a recent DFT calculations, the volumetric mismatch between bcc Cu and bcc Fe is about 5.4% (derived from 1.8% lattice mismatch) [48], larger than the value of 2.6% given above. Therefore, an even stronger elastic interaction between Cu and stress fields may exist than that predicted in this work.…”

Section: Interaction (Ev)mentioning

confidence: 63%

Preferential Cu precipitation at extended defects in bcc Fe: An atomistic study

Zhang

Millett

Tonks

et al. 2015

Computational Materials Science

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a b s t r a c tAs a starting point to understand Cu precipitation in RPV alloys, molecular dynamics and Metropolis Monte-Carlo simulations are carried out to study the effect of lattice defects on Cu precipitation by taking Fe-Cu system as a model alloy. Molecular dynamics simulations show that owing to the high heat of mixing and positive size mismatch, Cu is attracted by vacancy type defects such as vacancies and voids, and tensile stress fields. In accordance, preferential precipitation of Cu is observed in Metropolis Monte-Carlo simulations at dislocations, prismatic loops and voids. The interaction of Cu with a stress field, e.g., that associated with a dislocation or a prismatic loop, is dominated by elastic effect and can be well described by the linear-elasticity theory. For prismatic loops, the attraction to Cu is found to be size-dependent with opposite trends displayed by vacancy and interstitial loops. The size-dependences can be explained by considering the stress fields produced by these loops. The current results will be useful for understanding the effect of neutron irradiation on Cu precipitation in reactor-pressure-vessel steels.

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Section: Interaction (Ev)mentioning

confidence: 63%

Preferential Cu precipitation at extended defects in bcc Fe: An atomistic study

Zhang

Millett

Tonks

et al. 2015

Computational Materials Science

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“…58). In the study of Medvedeva et al, 59 negative interfacial Co segregation energies have been calculated by ab initio density-functional calculations. Co might segregate to grain boundaries in the Cu-26 at.% Co alloy resulting in a higher yield strength and hence, an enhanced Hall-Petch coefficient by suppressing dislocation emission from the boundaries, pinning them or hindering relaxation of the dislocation at the boundaries.…”

Section: Discussionmentioning

confidence: 99%

High strength nanocrystalline Cu–Co alloys with high tensile ductility

Bachmaier

Rathmayr²,

Schmauch

et al. 2018

J. Mater. Res.

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A supersaturated single-phase Cu-26 at.% Co alloy was produced by high-pressure torsion deformation, leading to a nanocrystalline microstructure with a grain size smaller than 100 nm. The nonequilibrium solid solution decomposed during subsequent isothermal annealing. In situ high-energy X-ray diffraction was used to map changes linked to the separating phases, and the development of a nanoscale Cu-Co composite structure was observed. To gain further information about the relationship of the microstructure and the mechanical properties after phase separation, uniaxial tensile tests were conducted on as-deformed and isothermally annealed samples. Based on the in situ diffraction data, different isothermal annealing temperatures were chosen. Miniaturized tensile specimens with a round cross section were tested, and an image-based data evaluation method enabled the evaluation of true stress-strain curves and strain hardening behavior. The main results are as follows: all microstructural states showed high strength and ductility, which was achieved by a combination of strain-hardening and strain-rate hardening.Andrea Bachmaier received her PhD in Materials Science at the University of Leobenin 2011. For her PhD research, she followed a novel strategy to produce supersaturated solidsolutions in immiscible alloy systems by a new two-step severe plastic deformation (SPD) process to obtain bulk specimens directly. Following graduation she spent two years in industry where she led a large research project funded by the Austrian Research Promotion Agency on advanced high-strength steels. In 2013, she was awarded an Erwin-Schrödinger scholarship that allowed her to work on the mechanisms behind bulk mechanical alloying, the decomposition process of supersaturated solid solutions and its influence on the thermal stability as well as on functional and mechanical properties. She leads a research group at the Erich Schmid Institute of Materials Science in Leoben Austria. Her current research primarily focuses on the generation of metastable materials, novel nanocomposites and nanocrystalline metal-matrix composites by SPD, and ERC Starting Grant funded program on SPD processed nanoscale magnetic materials. 58

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“…The large values of W ad obtained for the Fe layer on the Cr or Mn monolayer covering (0 0 1)NbC demonstrate that these impurities may provide a stronger bonding for the adsorbed Fe atoms and make the following Fe adsorption more efficient. Alloying additions segregated in the interfacial region between Fe and carbide may serve also as a barrier to dislocation motion through the interface resulting in additional hardening [49].…”

Section: Transition Metal Adsorption On (0 0 1)nbcmentioning

confidence: 99%