Positron annihilation studies on the migration of deformation induced vacancies in stainless steel AISI 316 L

Holzwarth, Uwe; Barbieri, A.; Hansen-Ilzhofer, S.; Schaaff, Petra; Haaks, M.

doi:10.1007/s003390100781

Cited by 26 publications

(16 citation statements)

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“…For higher annealing temperatures, the S-parameter decreases and follows the values obtained for two other samples. The values of the vacancy migration energies obtained from the model for four samples studied, i.e., 0.51-0.54 eV, are relatively low in comparison to, e.g., 0.9 eV obtained by Holzwarth et al for 316L SS for which deformation did not induce a 0 -martensite [38]. This confirms that the vacancy migration model does not describe well the S-parameter dependencies obtained for austenitic SS containing DIM because new defects are created during martensite reversion.…”

Section: Vickers Microhardness Measurementmentioning

confidence: 86%

“…These techniques have been successfully used for non-destructive evaluation of fatigue damage in SSs [31][32][33] and detection of the subsurface zone defects created by sliding, cutting [34,35], or shot peening [36]. PAS was applied to determine vacancy migration energy in SS [37,38]. Sensitivity of PAS is sufficient for investigation of the phase transformations in different materials [39,40], and this technique has been profitably applied in microstructural characterization of steels which are candidates for structural materials in nuclear facilities [41,42].…”

Section: Introductionmentioning

confidence: 99%

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Reverse transformation of deformation-induced martensite in austenitic stainless steel studied by positron annihilation

2014

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The reversion of deformation-induced a 0 -martensite in tension-deformed 1.4301 (EN) stainless steel was investigated using positron annihilation spectroscopy. The Doppler broadening of the annihilation line and positron lifetime spectroscopy were applied to study defect structure and its annealing behavior in samples with a similar deformation level but varying in a 0 -martensite amount. The difference in a 0 -martensite was obtained by applying different deformation temperatures, i.e., liquid nitrogen temperature, room temperature, and 200°C. The cumulative annealing of the tension-deformed samples and measurement of the positron annihilation characteristics show the gradual annealing of defects in the temperature range between 200 and 400°C due to the recovery and recrystallization. However, in the temperature range between 450 and 650°C, the generation of vacancy clusters which trap positrons is revealed. This temperature range coincides with the temperature range of a 0 -martensite reversion which is confirmed by microhardness and magnetization measurements. The detected large vacancy clusters consisting of 6-9 vacancies can occur at the interface between austenite and a 0 -martensite phases due to the volume contraction accompanying bcc/fcc change.

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Section: Vickers Microhardness Measurementmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Reverse transformation of deformation-induced martensite in austenitic stainless steel studied by positron annihilation

2014

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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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“…This allows incorporating the spatial distribution of vacancies into the simple trapping model. This model allows describing the experimental results obtained in the isothermal and isochronal measurements of the highly deformed Ag [24] and stainless steel [25]. The review of the models points out a wide application of the annihilation methods to variety of problems at different scales.…”

Section: Standard Trapping Modelmentioning

confidence: 99%

Positron annihilation studies of recrystallization in the subsurface zone induced by friction in magnesium—effect of the inhomogeneity on measured positron annihilation characteristics

Dryzek

2013

Appl. Phys. A

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The discussion of the positron annihilation studies of crystal structure defects, like vacancies, dislocations, grain boundaries and the defect depth profile, is presented. The role of the positron implantation depth and positron diffusion in such studies has been considered in detail. For description of the measured annihilation characteristics the proposed theoretical models take into account both effects. The annealing studies of defects created in pure magnesium by compression or dry sliding-wear were used for demonstration of the discussed thesis. The positron lifetime measurements were applied for monitoring open volume defects behavior. It was demonstrated that annealing at the temperature of about 300°C removes the defects created by compression. Application of the proposed model to description of the data obtained allows to determine the activation energy of the grain boundary mobility in pure magnesium equal to Q = 0.56 ± 0.18 eV. However, defects created by the dry sliding are not completely annealed up to the temperature of 500°C. The defect depth profile induced by dry sliding evolves with the annealing temperature in such a way that at the worn surface concentration of defects gradually decreases but at the depth between 60 and 100 µm the generation of new defects takes place at temperature of 150 and 225°C. Above 300°C the defects still are extended up to the depth of about 80 µm.

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Positron annihilation studies on the migration of deformation induced vacancies in stainless steel AISI 316 L

Cited by 26 publications

References 0 publications

Reverse transformation of deformation-induced martensite in austenitic stainless steel studied by positron annihilation

Reverse transformation of deformation-induced martensite in austenitic stainless steel studied by positron annihilation

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

Positron annihilation studies of recrystallization in the subsurface zone induced by friction in magnesium—effect of the inhomogeneity on measured positron annihilation characteristics

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