Self-diffusion and fast cobalt impurity diffusion in the bulk and in grain boundaries of hexagonal titanium

Herzig, Christian; Willecke, R.; Vieregge, K.

doi:10.1080/01418619108213927

Cited by 92 publications

(26 citation statements)

References 24 publications

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“…3 and Eq. 4, Figure 4 shows from less pure specimens, 19 but less than the measured Q ⊥ (3.14 eV) from ultrapure specimens. 20 For the sake of convenience, the diffusion-relative properties are also summarized in Table I.…”

Section: B Self-diffusion Coefficientsmentioning

confidence: 99%

“…Of notable significance are the following: (i) there is a large difference (> 0.5 eV) in the vacancy formation energy in Ti from experiments [12][13][14] and first-principles predictions; 11,[15][16][17] (ii) self-diffusion coefficients and activation energies from measurements are scattered (see details later); [18][19][20] (iii) existing studies of vacancy migration are incomplete, and hence the anomalous energy pathway for vacancy migration within a Ti basal plane with double saddle points, the subject of the present work, has not been reported. 11,16 Numerous experimental difficulties render determination of diffusion properties in hcp materials challenging, with the most daunting issues being specimen purity, the availability of radioactive tracer elements, and large experimental uncertainties.…”

Section: Introductionmentioning

confidence: 99%

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Anomalous energy pathway of vacancy migration and self-diffusion in hcp Ti

et al. 2011

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An anomalous energy pathway with energetically-equivalent double saddle points for vacancy mediated self-diffusion within an hcp-Ti basal plane is unveiled by density functional theory.Examination of migration pathway and phonon force constants suggests that the migrating atom tries to follow the bcc-hcp phase transition via the Burgers shear deformation. We propose that the formed energy local minimum with a bcc-like atomic environment between the two saddle points originates from the existence of high-temperature bcc phase and is a feature of Group IV hcp metals with bcc-hcp phase transition. Computed diffusion coefficients are in favorable accord with experiments for hcp Ti. PACS numbers: 66.30.Fq, 63.20.dk, 82.20.Db 2

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Section: B Self-diffusion Coefficientsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anomalous energy pathway of vacancy migration and self-diffusion in hcp Ti

et al. 2011

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“…A feature diagonal elements of the matrix of self-diffusion of the many-body interatomic potential for Zr used here [11] coefficients, D* kk , are written as is that it describes the HCP structure to be stable up to the melting point (2120 K). This permitted the use of rather D* kk ϭ R 2 kk 2t [1] high temperature, up to 1650 K, where the necessary statistics, i.e., 2500 to 3000 jumps, were collected in a reasonable where k is 1, 2, or 3 (corresponding to rectangular Cartesian time. However, high temperature simulation did not demonaxes), and R 2 kk is the kk component of mean square displacestrate a recognizable anisotropy for the vacancy, and so, we ment (MSD) of the tracer atoms.…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of point defect diffusion in alpha-zirconium

Osetsky

Bacon

Diego

2002

Metall Mater Trans A

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Two types of intrinsic defect, i.e., vacancy and self-interstitial atom (SIA), are formed in metals during irradiation with energetic particles. The evolution of defect population leads to significant changes in microstructure and causes a number of radiation-induced property changes. Some phenomena, such as radiation growth of anisotropic materials, are due to anisotropy in the atomic mass transport by point defects. Detailed information on atomic-scale mechanisms is, therefore, necessary to understand such phenomena. In this article, we present results of a computer simulation study of mass transport via point defects in alpha-zirconium. The matrix of self-diffusion coefficients and activation energies for vacancy and SIA defects have been obtained, and different methods of treatment of diffusion have been tested. Molecular dynamics (MD) shows that vacancy diffusion is approximately isotropic in the temperature range studied (1050 to 1650 K), although some preference for basalplane diffusion was observed at the lower end of the range. The mechanism of interstitial diffusion changes from one-dimensional (1-D) in a ͗1120͘ direction at low temperature (Ͻ300 K) to twodimensional (2-D) in the basal plane and, then, three-dimensional (3-D) at higher temperatures.

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“…Selfdiffusion in an extended temperature range in low pure hcpTi was measured by Herzig et al [10] The self-diffusion of Ti of 99.9% (40 at ppm of Fe content) in the range of 776 to 1132 K was measured by Pérez et al [11] using the intergrated backscatter (IBS) technique. The self-diffusion of high purity hcp-Ti was measured by Köppers et al [12] Pérez et al [13] had previously performed measurements of diffusion of Sn in less pure hcp-Ti with the same Backscattering Spectrometry (RBS) technique.…”

Section: Literature Reviewmentioning

confidence: 99%

Computational Study of Mobilities and Diffusion in Ti-Sn Alloy

Wang

Liu

Tuo

et al. 2015

J. Phase Equilib. Diffus.

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Based on the thermodynamic parameters and experimental diffusion data in the literature, the atomic mobilities of bcc Ti-Sn alloys are assessed by the CALPHAD method using DICTRA software package, and boundary mobility parameters of hcp Ti-Sn alloys were also given in the work. Compared with the calculated and measured diffusion coefficients of bcc Ti-Sn, most of the experimental data are reproduced well. The composition-distance profiles of Ti/Ti-4.9 at.% Sn diffusion couple at 1223 K for 14.4 ks were also predicted using the assessed mobility parameters. It is hopeful to provide useful guidance for the design of Ti-based alloys.

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Self-diffusion and fast cobalt impurity diffusion in the bulk and in grain boundaries of hexagonal titanium

Cited by 92 publications

References 24 publications

Anomalous energy pathway of vacancy migration and self-diffusion in hcp Ti

Anomalous energy pathway of vacancy migration and self-diffusion in hcp Ti

Anisotropy of point defect diffusion in alpha-zirconium

Computational Study of Mobilities and Diffusion in Ti-Sn Alloy

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