Dislocation studies on deformed single crystals of high-purity iron using positron annihilation: Determination of dislocation densities

Park, Yong-Ki; Waber, J.T.; Meshii, M.; Snead, C.L.; Park, C. G.

doi:10.1103/physrevb.34.823

Cited by 94 publications

(41 citation statements)

References 29 publications

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“…Since specific trapping rates for vacancies and dislocations in LaNi 5 are not known, we adopt here the specific trapping rates for vacancies and dislocations in most metals, µ vac ≈ 10 14 ∼10 15 s −127, 28) and µ dis ≈ 0.1∼1 cm 2 s −1 , 29) respectively. The dislocation density measured by Wu et al 13) by means of neutron powder diffractometry, ρ = 4.8 × 10 12 cm −2 , and the relative intensity for vacancies, 0.72, just after the first absorption-desorption treatment, give us the concentration of vacancies formed by hydriding in LaNi 5 as 10 −3 -10 −1 .…”

Section: Discussionmentioning

confidence: 99%

Recovery of Hydrogen Induced Defects and Thermal Desorption of Residual Hydrogen in LaNi<SUB>5</SUB>

2002

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Lattice defects induced by initial hydriding and their effect on residual hydrogen content in LaNi 5 have been studied by means of positron lifetime spectroscopy and hydrogen thermal desorption measurement. Component analyses of positron lifetime spectra show that surprising amount of vacancies together with dislocations are generated by the initial hydriding. Vacancy migration in LaNi 5 after hydrogen desorption at room temperature is observed around 423-673 K, while dislocations in LaNi 5 are much more stable. Hydrogen thermal desorption measurement shows that the release of residual hydrogen occurs mainly in the temperature range from 450 to 650 K, and it ceases at about 800 K. The release temperature of residual hydrogen closely corresponds with the temperature of vacancy migration and annihilation in LaNi 5 . Residual hydrogen in LaNi 5 is most likely trapped by vacancies and vacancy clusters, which are induced by hydriding.

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Section: Discussionmentioning

confidence: 99%

Recovery of Hydrogen Induced Defects and Thermal Desorption of Residual Hydrogen in LaNi<SUB>5</SUB>

2002

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“…(1) The positron trapping rate for vacancy κ v can be calculated as [12,15]. Figure 3 shows the relation between the mean lifetime for positrons (τ m ) and the vacancy concentration C v with the Si content.…”

Section: Fesimentioning

confidence: 99%

A Study of Defects in Iron Based Alloys by Positron Annihilation Techniques

et al. 2008

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“…One of the most important parts of these studies is dedicated to expanding the knowledge about behaviour of structural defects such as vacancies, impurities, or dislocations existing or created in the materials during their utilization [1][2][3][4][5][6][7][8][9]. This behaviour is crucial for better understanding diffusion and alloying processes as well as mechanical, thermodynamic, and magnetic properties of the alloys under consideration.…”

Section: Introductionmentioning

confidence: 99%

Behaviour of vacancies in dilute Fe–Re alloys: a positron annihilation study

Idczak

Konieczny

2014

Appl. Phys. A

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Positron annihilation lifetime spectroscopy was used in a room temperature study of the influence of heat treatment on behaviour of vacancies in Fe 0.97 Re 0.03 and Fe 0.94 Re 0.06 alloys. In this experiment, the vacancies were created during the formation and further mechanical processing of the iron systems under consideration so the lifetime spectra of positrons were collected at least twice. The first samples were taken just after the melting process in an arc furnace, and the second ones were taken for the specimens annealed at 1,270 K and then cold-rolled at room temperature. After that, the spectra were measured for all studied samples after annealing at some temperatures gradually increasing from 300 to 1,270 K. It was found that vacancy-Re pairs are the dominant type of structural defects in alloys just after the melting process. In the case of alloys after a cold rolling process, the dominant type of structural defects is vacancies associated with edge dislocations. Moreover, for cold-rolled samples annealed at 473-573 K, the growth of the vacancy clusters associated with edge dislocations is observed by an increase in the mean positron lifetime. Finally, at temperatures above 573 K, vacancy clusters associated with edge dislocations as well as vacancy-Re pairs become unstable, and freely migrating vacancies sink at grain boundaries.

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Dislocation studies on deformed single crystals of high-purity iron using positron annihilation: Determination of dislocation densities

Cited by 94 publications

References 29 publications

Recovery of Hydrogen Induced Defects and Thermal Desorption of Residual Hydrogen in LaNi<SUB>5</SUB>

Recovery of Hydrogen Induced Defects and Thermal Desorption of Residual Hydrogen in LaNi<SUB>5</SUB>

A Study of Defects in Iron Based Alloys by Positron Annihilation Techniques

Behaviour of vacancies in dilute Fe–Re alloys: a positron annihilation study

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