Non-equilibrium Grain Boundary Wetting in Cu–Ag Alloys Containing W Nanoparticles

Shu, Shipeng; Zhang, Xuan; Bellon, Pascal; Averback, Robert S

doi:10.1080/21663831.2015.1090496

Cited by 3 publications

(4 citation statements)

References 19 publications

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“…Very different precipitate morphologies have been observed in systems with two distinct precipitating phases [1]. These include core-shell structures [2,3], second-phase appendages (side-by-side coprecipitate) [4][5][6][7], or simply two spatially separate populations of precipitates [8][9][10]. These microstructures are determined by the coupling of many complex thermodynamic and kinetic factors.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics and kinetics of core-shell versus appendage co-precipitation morphologies: An example in the Fe-Cu-Mn-Ni-Si system

Shu¹,

Wells²,

Almirall³

et al. 2018

Acta Materialia

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What determines precipitate morphologies in co-precipitating alloy systems? We focus on alloys of two precipitating phases, with the fast-precipitating phase acting as heterogeneous nucleation sites for a second phase manifesting slower kinetics. Kinetic lattice Monte Carlo simulations show that the interplay between interfacial and ordering energies, plus active diffusion paths, strongly affect the selection of core-shell verses appendage morphologies. We study a FeCuMnNiSi alloy using the combination of atom probe tomography and simulations, and show that the ordering energy reduction of the MnNiSi phase heterogeneously nucleated on a pre-existing copper-rich precipitate exceeds the energy penalty of a predominantly Fe/Cu interface, leading to initial appendage, rather than core-shell, formation. Diffusion of Mn, Ni and Si around and through the Cu core towards the ordered phase results in subsequent appendage growth. We further show that in cases with higher primary precipitate interface energies and/or suppressed ordering, the coreshell morphology is favored.3

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Section: Introductionmentioning

confidence: 99%

Thermodynamics and kinetics of core-shell versus appendage co-precipitation morphologies: An example in the Fe-Cu-Mn-Ni-Si system

Shu¹,

Wells²,

Almirall³

et al. 2018

Acta Materialia

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“…On the other hand, Cu/Ag alloys prepared by physical vapor deposition and subsequent annealing have Ag grains comparable in size to Cu grains, although formation of GB wetting layers of Ag can also be achieved in this synthesis method by adding tungsten. 15 Not only the type of the synthesis technique but also the details of the synthesis process can have a strong influence on the microstructure. For example, the dominant types of Cu/Ag interfaces formed during casting can be controlled by setting the furnace removal rate.…”

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confidence: 99%

Morphology and mechanical properties of nanocrystalline Cu/Ag alloy

Szlufarska

2017

J Mater Sci

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Hybrid Monte Carlo (MC)/molecular dynamics (MD) simulations are conducted to study the microstructures of nanocrystalline (nc) Cu/Ag alloys with various Ag concentrations. When the Ag concentration is below 50 Ag atoms/nm!, an increase in Ag concentration leads to a gradual growth of monolayer grain boundary (GB) complexions into nanolayer complexions. Above the concentration of 50 Ag atoms/nm!, wetting layers with a bulk crystalline phase are observed. The effects of Ag on mechanical properties and deformation mechanisms of nc Cu/Ag alloys are investigated in MD simulations of uniaxial tension. GB sliding resistance is found to first increase and then decrease with an increase in Ag concentration. Surprisingly, we also find that the dislocation density decreases monotonically with an increase in Ag concentration, which suggests that the grain interiors are softened by the introduction of Ag dopants at GBs. In addition, there is a critical Ag concentration that maximizes flow stress of nc Cu/Ag alloys. The flow stress, GB sliding resistance, and the intragranular dislocation densities become less sensitive to Ag dopants when the grain diameter increases from 5nm to 40nm

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“…The first RT irradiation step is performed to nucleate a high density of W nano-precipitates with diameters  1-2 nm [14,15]. This pre-irradiation treatment also increases the average grain size from less than ~ 50 nm to ~ 200 nm.…”

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confidence: 99%

“…The samples were characterized using scanning transmission electron microscopy (STEM). [14,16,17], taking an elongated, rod-like shape. We consider a W precipitate to be a "W rod" if its aspect ratio is greater than 3.…”

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Irradiation-induced formation of nanorod precipitates in a dilute Cu–W alloy

et al. 2016

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Radiation-enhanced precipitation of W has been investigated in dilute Cu-W alloys. While spherical W precipitates are stabilized during irradiation below ~ 300 ˚C and above ~ 600 ˚C, irradiation at 500˚C results in the formation of nanorods. Furthermore, use of two-step irradiations, first one at 600 ˚C followed by one at 500˚C, indicates that the morphological transformation is reversible. The stabilization of W nanorods is rationalized using a model introduced by Frost and Russell to explain size stabilization of precipitates formed during irradiation, but extended here to consider precipitate morphology.

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Non-equilibrium Grain Boundary Wetting in Cu–Ag Alloys Containing W Nanoparticles

Cited by 3 publications

References 19 publications

Thermodynamics and kinetics of core-shell versus appendage co-precipitation morphologies: An example in the Fe-Cu-Mn-Ni-Si system

Thermodynamics and kinetics of core-shell versus appendage co-precipitation morphologies: An example in the Fe-Cu-Mn-Ni-Si system

Morphology and mechanical properties of nanocrystalline Cu/Ag alloy

Irradiation-induced formation of nanorod precipitates in a dilute Cu–W alloy

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