FEM analysis based on the 3D-NCS model for precipitate morphology in the BCC/HCP system

Miyano, Naoki; Ameyama, Kei; Hirano, Noriyoshi; Takao, Yoshihiro

doi:10.1016/j.msea.2007.08.014

Cited by 8 publications

(6 citation statements)

References 8 publications

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“…12) In the 3D-NCS model, a high-density plane and the direction of the near-coincidence atoms imply a good atomic matching plane and a small-misfit direction between a matrix and a precipitate, respectively. 13) In a previous study, 8) the density of the near-coincident atoms on all the planes that are along the invariant line direction was examined for investigating the preferred habit planes because each habit plane of the precipitate involves the invariant line, 14,15) which was revealed by TEM observations. 8) The results are shown in Fig.…”

Section: Atomic Matching Modelmentioning

confidence: 99%

“…The atomic matching model is unable to predict the habit plane in BCC/ HCP systems since the anisotropic characteristics of these systems are distinct as compared to those of the FCC/BCC systems. For instance, in the case of Ti-22V-4Al alloy, the atomic matching ratio of the broadest habit plane in the precipitate is almost half that of the second habit plane, 8) although the total interphase energy becomes lower if the precipitate is surrounded by a higher atomic matching habit plane. This is a common tendency in BCC/HCP system alloys such as Zr-Nb 9) and Ti-7Cr.…”

Section: Introductionmentioning

confidence: 99%

“…Few researches have considered the crystallographic orientation relationship (OR) and anisotropy elastic strain in diffusional phase transformation. Therefore, in our previous study, 8) we have described the entire shape of the precipitate in Ti-22V-4Al in terms of the interphase and elastic strain energies generated between the precipitate and matrix by using the finite element method (FEM) analysis, which can calculate the anisotropic elastic strain depending on the shape of the precipitate and the OR between the precipitate and the matrix. The analysis results with regard to the precipitate are compared with the TEM results; the analysis results correspond well with the observations.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of Precipitate Morphology by Atomic Matching Model and FEM Analysis with Consideration of Anisotropy Elastic Strain in a BCC/HCP system

et al. 2008

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This study focuses on the entire shape of the precipitate in Ti-22V-4Al in terms of the interphase and elastic strain energies generated between the precipitate and matrix. In order to consider a transformation strain, the volumetric strain and strain relaxation by a misfit dislocation on the interphase boundary are calculated. Firstly, the atomic matching model is employed for determining the preferred habit planes by evaluating the results of geometrical atomic matching. Subsequently, the precipitate configuration that consists of the preferred habit plane is determined by the elastic strain with the minimum value. Then, the elastic strain surrounding and within the predicted precipitate is examined by an FEM analysis, which can be used to calculate the anisotropic elastic strain depending on the shape of the precipitate. A comparison of these results with regard to the precipitate observed by TEM elucidates the determination of the ideal shape of the precipitates in BCC/HCP systems; the optimum configuration of the precipitate that consists of the preferred habit plane is determined by the tradeoff relationship of two factors; one is the strain relaxation due to an increment in the broad face plane, and the other is the decrease in the total elastic strain as the surface ratio approaches a regular square.

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Section: Atomic Matching Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Prediction of Precipitate Morphology by Atomic Matching Model and FEM Analysis with Consideration of Anisotropy Elastic Strain in a BCC/HCP system

et al. 2008

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“…FEM has successfully been used for the simulation and study of the precipitation process in various systems. The strain energy increase associated with precipitation [9] and the morphology of the precipitates [10] have been analyzed using FEM. The technique has also been proved useful in the determination of stresses associated with phase transformations [11] and in the study of long-range internal stresses in superalloys [12].…”

Section: Introductionmentioning

confidence: 99%

Critical sizes for coherent to semicoherent transition in precipitates

Kumar

Kaur

Subramaniam

2013

International Journal of Materials Research

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Critical sizes for coherent to semicoherent transition in precipitates A coherent precipitate, on growth beyond a critical size, can become semicoherent through the formation of interfacial misfit dislocations. This investigation pertains to the finite element simulation of the state of stress of a coherent precipitate, its growth and the change in state of stress on the formation of an interfacial misfit dislocation loop. Critical radii are determined from the simulations based on: (i) global energy minimum (r*) and (ii) local force balance along the radial direction (r c). The concept of local force balance as existing in literature is extended to the circumferential direction, to calculate a new critical size (r t). Local force balance gives radii at which the interface is the stable position for the dislocation loop. Off-interface stability of the dislocation loops is also investigated. The Cu-cFe system is used as an example to illustrate the new methodology developed and validate the results of the simulation. The power of the methodology is shown by considering a configuration (precipitation in a thin disc), where standard theoretical formulations are inadequate.

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“…Experimental investigations on the formation of multiple dislocation loops also exist in literature [7,8], along with theoretical work (addressing certain aspects of the process) [9]. The finite element method (FEM) has proved to be a useful tool in the study of both precipitation [10,11] and dislocations [12,13].…”

Section: Introductionmentioning

confidence: 99%

On the Formation and Stability of Two Misfit Dislocations in the Cu-γFe System

Kumar

Gautam

Subramaniam

2013

JMMP

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On growth beyond a critical size coherent precipitates become semicoherent by the formation of an interfacial misfit edge dislocation loop. On further growth of the precipitate, the interface progressively loses its coherency by the formation of additional dislocation loops. The current investigation pertains to the energetic feasibility of two dislocation loops. Finite element simulations are performed to simulate the stress state of the semicoherent precipitate and to compute the radius of the precipitate at which two symmetrically positioned dislocation loops become energetically favourable. Aspects regarding the stability of the loops are also explored using the simulations. Cu-γFe system is used as a model system to illustrate the methodology and to capture the essential aspects of the process.

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FEM analysis based on the 3D-NCS model for precipitate morphology in the BCC/HCP system

Cited by 8 publications

References 8 publications

Prediction of Precipitate Morphology by Atomic Matching Model and FEM Analysis with Consideration of Anisotropy Elastic Strain in a BCC/HCP system

Prediction of Precipitate Morphology by Atomic Matching Model and FEM Analysis with Consideration of Anisotropy Elastic Strain in a BCC/HCP system

Critical sizes for coherent to semicoherent transition in precipitates

On the Formation and Stability of Two Misfit Dislocations in the Cu-γFe System

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