Thermal stability of electrodeposited nanocrystalline Ni–Co alloys

Hibbard, G.D.; Aust, K.T.; Erb, U.

doi:10.1016/j.msea.2006.06.096

Cited by 87 publications

(43 citation statements)

References 14 publications

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“…Pulsed electrodeposition has been employed successfully for processing nanocrystalline materials in bulk, [51] most notably, Ni-Fe and Ni-Co alloys. [69,70] However, synthesis of nanocrystalline alloys or metals by electrodeposition often requires use of additives for the purpose of biasing nucleation over growth of the depositing grains. These additives are believed [4] to remain in the material as impurities and may cause poor mechanical properties (such as embrittlement), typically observed in nanocrystalline electrodeposits.…”

Section: B Synthesis Of Nanocrystalline Alloysmentioning

confidence: 99%

Role of Nanostructure in Electrochemical Corrosion and High Temperature Oxidation: A Review

Mahesh

Raman

2014

Metall Mater Trans A

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The extremely fine grain size of nanocrystalline (nc) metallic alloys results in significantly different mechanical, electrochemical and oxidation properties as compared to the coarse-grained alloys of the same composition. Although the synthesis and attractive mechanical properties of nanocrystalline materials have been investigated and reviewed in great depth, the high temperature oxidation and electrochemical corrosion of these materials has received limited attention. The difference in the active dissolution and passivation behavior of nc alloys as compared to their microcrystalline counterparts varies for each alloy system. However, a unified theory explaining these phenomena still eludes us. In this context, this article reviews the progress in the electrochemical corrosion behavior of different nanocrystalline alloys, and hence, develops a better understanding of the effect of grain size, composition, interfacial phenomena and selective dissolution on corrosion of nanocrystalline alloys. This review also presents the role of nanometric grain size and the associated increase in grain boundary diffusion on the high temperature oxidation of nc alloys. The attractive possibility of enhanced oxidation resistance at lower alloying additions as compared to the coarse-grained alloys has been discussed. Although the primary focus of the article is on ferrous alloy systems, however, the lead studies on the role of ultrafine grain size in oxidation/corrosion behavior of other alloys systems have also been reviewed.

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Section: B Synthesis Of Nanocrystalline Alloysmentioning

confidence: 99%

Role of Nanostructure in Electrochemical Corrosion and High Temperature Oxidation: A Review

Mahesh

Raman

2014

Metall Mater Trans A

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“…13,17,20 However, the onset of microstructural evolution in a range of nanocrystalline metals often transpires through an abnormal growth process, which has been observed in copper, 21,22 nickel, 21,23 iron, 24 palladium, 13 and cobalt 15 as well as a number of binary nanocrystalline alloys. [25][26][27] As the average grain size increases from the nanocrystalline to the ultrafine grain regime, abnormal grain growth widely succumbs to curvature-driven mechanisms, 28 thus underscoring the importance of stabilizing the nanostructure collectively against the initial and late stages of grain growth in nanocrystalline metals.…”

Section: Introductionmentioning

confidence: 99%

Solute stabilization of nanocrystalline tungsten against abnormal grain growth

et al. 2017

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Microstructure and phase evolution in magnetron sputtered nanocrystalline tungsten and tungsten alloy thin films are explored through in situ TEM annealing experiments at temperatures up to 1000°C. Grain growth in unalloyed nanocrystalline tungsten transpires through a discontinuous process at temperatures up to 550°C, which is coupled to an allotropic phase transformation of metastable b-tungsten with the A-15 cubic structure to stable body centered cubic (BCC) a-tungsten. Complete transformation to the BCC a-phase is accompanied by the convergence to a unimodal nanocrystalline structure at 650°C, signaling a transition to continuous grain growth. Alloy films synthesized with compositions of W-20 at.% Ti and W-15 at.% Cr exhibit only the BCC a-phase in the as-deposited state, which indicate the addition of solute stabilizes the films against the formation of metastable b-tungsten. Thermal stability of the alloy films is significantly improved over their unalloyed counterpart up to 1000°C, and grain coarsening occurs solely through a continuous growth process. The contrasting thermal stability between W-Ti and W-Cr is attributed to different grain boundary segregation states, thus demonstrating the critical role of grain boundary chemistry in the design of solute-stabilized nanocrystalline alloys. transition with a focus on harsh environment sensors produced by additive manufacturing processes. Professor Trelewicz's research is on the science of interface engineered alloys with particular emphasis on high-strength and radiation-tolerant nanomaterials for extreme environment applications. His group couples in situ and analytical characterization tools with large-scale atomistic simulations to explore the thermal stability, mechanical behavior, and radiation tolerance of solute-stabilized nanocrystalline alloys, crystalline-amorphous nanolaminates, metallic glass matrix composites, and other unique hierarchical metallic structures. Professor Trelewicz is a recipient of the 2017 DOE Early Career

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“…Alloying has the potential to suppress the instability of pure nanocrystalline materials, as evidenced by the enhanced thermal stability of a number of binary nanocrystalline alloys relative to their single-component counterparts. 14,[21][22][23][24] While such behavior has been traditionally linked to kinetic phenomena such as solute drag, 25 recent studies have suggested that nanocrystalline alloys could in fact be thermodynamically stabilized by solute enrichment at the grain boundaries. [26][27][28] The idea of segregation-induced thermodynamic stability in nanocrystalline solids was first addressed analytically by Weissmüller, [28][29][30] who considered the change in the Gibbs free energy of a polycrystal upon alloying.…”

Section: Introductionmentioning

confidence: 99%

Grain boundary segregation and thermodynamically stable binary nanocrystalline alloys

2009

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A free-energy function for binary polycrystalline solid solutions is developed based on pairwise nearestneighbor interactions. The model permits intergranular regions to exhibit unique energetics and compositions from grain interiors, under the assumption of random site occupation in each region. For a given composition, there is an equilibrium grain size, and the alloy configuration in equilibrium generally involves solute segregation. The present approach reduces to a standard model of grain boundary segregation in the limit of infinite grain size, but substantially generalizes prior thermodynamic models for nanoscale alloy systems. In particular, the present model allows consideration of weakly segregating systems, systems away from the dilute limit, and is derived for structures of arbitrary dimensionality. A series of solutions for the equilibrium alloy configuration and grain size are also presented as a function of simple input parameters, including temperature, alloy interaction energies, and component grain boundary energies.

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Thermal stability of electrodeposited nanocrystalline Ni–Co alloys

Cited by 87 publications

References 14 publications

Role of Nanostructure in Electrochemical Corrosion and High Temperature Oxidation: A Review

Role of Nanostructure in Electrochemical Corrosion and High Temperature Oxidation: A Review

Solute stabilization of nanocrystalline tungsten against abnormal grain growth

Grain boundary segregation and thermodynamically stable binary nanocrystalline alloys

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