The coarsening behavior of the γ′ precipitate in nickel-silicon alloys

Rastogi, P. K.; Ardell, A.J.

doi:10.1016/0001-6160(71)90099-x

Cited by 165 publications

(32 citation statements)

References 11 publications

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“…The data on the other four binary alloys were taken from the following sources: Ni-Ga [15,16], Ni-Ge [17,18], Ni-Si [52], and Ni-Ti [49]. The fits to the collective data on each alloy are shown in Fig.…”

Section: Examination Of the Data On Binary Ni Alloysmentioning

confidence: 99%

A1-L12 interfacial free energies from data on coarsening in five binary Ni alloys, informed by thermodynamic phase diagram assessments

Ardell

2011

J Mater Sci

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The data on coarsening of c 0 -type precipitates (Ni 3 X, with the L1 2 crystal structure) in Ni-Al, Ni-Ga, Ni-Ge, Ni-Si, and Ni-Ti alloys are re-evaluated in the context of recent (TIDC) and classical (LSW) theories of coarsening, with the objective of ascertaining the best values possible of interfacial free energies, r, of the c/c 0 interfaces in these five alloy systems. The re-evaluations include fitting of the particle size distributions, reanalyzing all the available data on the kinetics of particle growth and kinetics of solute depletion, and using thermodynamic assessments of the binary alloy phase diagrams to calculate curvatures of the Gibbs free energies of mixing. The product of the work is two sets of interfacial free energies, one set for the analysis using the recent TIDC theory and the other for the analysis using the classical LSW theory. The TIDC-based analysis yields lower values of r by about a factor of 2/3. All the interfacial energies are considerably larger, by factors ranging from *4 to 10, than those previously reported, which were for the most part calculated from data on coarsening assuming idealsolution thermodynamics. In the TIDC theory the width of the interface, d, is allowed to increase with particle size, r. A simple equation relating r to the ratio of the gradient energy and d is used to show that r can remain constant even though d increases with r. Published work supporting this contention is presented and discussed.

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Section: Examination Of the Data On Binary Ni Alloysmentioning

confidence: 99%

A1-L12 interfacial free energies from data on coarsening in five binary Ni alloys, informed by thermodynamic phase diagram assessments

Ardell

2011

J Mater Sci

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“…The remaining part of the evolution equation [4] that is yet to be determined is the Lagrange parameter k b which would conserve the volume during interface evolution. Volume conservation is affected through the constraint,…”

Section: Conservation Of Volumementioning

confidence: 99%

“…[4] along with the equation of mechanical equilibrium at each time step, until a converged shape is reached.…”

Section: Mechanical Equilibriummentioning

confidence: 99%

“…[4], written for simplicity for the case of isotropic interfacial energy. We transform this equation into a coordinate system that is normal to the interface at a given location where the order parameter is being updated.…”

Section: Comparison With Previous Modelsmentioning

confidence: 99%

“…The mechanical properties of these alloys predominantly depend on precipitate size, morphologies, and their distribution. Thus, there are several experimental studies carried out which focus on the precipitate morphology, [1,2] their growth and coarsening, [3][4][5][6] strengthening. [7,8] In this regard, there are two mechanisms, one in which the precipitates are large enough such that there is no coherency between the precipitate and the matrix from which it is formed, and the second in which the precipitates are small such that there is still substantial coherency between the matrix and the precipitate.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Phase-Field Modeling of Equilibrium Precipitate Shapes Under the Influence of Coherency Stresses

Bhadak

Sankarasubramanian

Choudhury

2018

Metall Mater Trans A

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Coherency misfit stresses and their related anisotropies are known to influence the equilibrium shapes of precipitates. Additionally, mechanical properties of the alloys are also dependent on the shapes of the precipitates. Therefore, in order to investigate the mechanical response of a material which undergoes precipitation during heat treatment, it is important to derive the range of precipitate shapes that evolve. In this regard, several studies have been conducted in the past using sharp-interface approaches where the influence of elastic energy anisotropy on the precipitate shapes has been investigated. In this paper, we propose a diffuse interface approach which allows us to minimize grid-anisotropy-related issues applicable to sharp-interface methods. In this context, we introduce a novel phase-field method where we minimize the functional consisting of the elastic and surface energy contributions while preserving the precipitate volume. Using this technique, we reproduce the shape bifurcation diagrams for the cases of pure dilatational misfit that have been studied previously using sharp-interface methods and then extend them to include interfacial energy anisotropy with different anisotropy strengths which has not been a part of previous sharp-interface models. While we restrict ourselves to cubic anisotropies in both elastic and interfacial energies in this study, the model is generic enough to handle any combination of anisotropies in both the bulk and interfacial terms. Further, we have examined the influence of asymmetry in dilatational misfit strains along with interfacial energy anisotropy on precipitate morphologies.

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Development of Ni‐4 wt.% Si thermoseeds for hyperthermia cancer treatment

Chen¹,

Poirier²,

Damento³

et al. 1988

J. Biomed. Mater. Res.

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Ferromagnetic alloys, used in the form of "thermoseeds" for surgical implantation, have been developed and used to induce localized hyperthermia in cancerous growths. Alloys of nickel with approx. 4 wt.% Si were chosen for this study because they have Curie temperatures in the desired range of 45-60 degrees C. The thermoseeds were prepared by using either a special casting technique or casting and swaging followed by homogenization. The effects of these different processing schedules on the magnetic behavior of these alloys are discussed. In particular, the importance of minimizing oxidation during melting and heat treating, and the effects of homogenizing the thermoseeds on the relative permeability at temperatures near the Curie temperature are pointed out. The best processing schedule is casting small ingots while avoiding oxidation, followed by swaging, drawing, and homogenization. Actual induction heating experiments and the results from magnetization tests indicate that Ni-4 wt.% Si alloys prepared in this manner can be used as thermoseeds with predictable Curie temperatures. These thermoseeds can be used to obtain nearly uniform and constant temperatures in tumors with variable blood flows.

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The coarsening behavior of the γ′ precipitate in nickel-silicon alloys

Cited by 165 publications

References 11 publications

A1-L12 interfacial free energies from data on coarsening in five binary Ni alloys, informed by thermodynamic phase diagram assessments

A1-L12 interfacial free energies from data on coarsening in five binary Ni alloys, informed by thermodynamic phase diagram assessments

Phase-Field Modeling of Equilibrium Precipitate Shapes Under the Influence of Coherency Stresses

Development of Ni‐4 wt.% Si thermoseeds for hyperthermia cancer treatment

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