Static and dynamical ageing processes at room temperature in a Fe25Ni0.4C virgin martensite : effect of C redistribution at the nanoscale - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Philosophical Magazine Letters Année : 2013

Static and dynamical ageing processes at room temperature in a Fe25Ni0.4C virgin martensite : effect of C redistribution at the nanoscale

Résumé

The work-hardening behaviour of virgin martensitic steel has been investigated in a strictly un-aged state and after various ageing conditions. At room temperature (RT), the un-aged alloy shows astonishing tensile performances (ultimate tensile stress = 1600 MPa/uniform elongation = 15%) but unexpected serrations. These serrations can be suppressed by static ageing (at RT or higher) while maintaining the initial work-hardening rate (ageing at RT). Parallel investigations using atom probe tomography reveal that the distribution of carbon at the atomic scale evolves from purely homogeneous for virgin martensite to partly segregated at a very fine scale (5-10 nm) after static ageing. This particular mechanical behaviour can therefore be associated with a very local decrease in available carbon in solid solution due to redistribution and segregations on defects (nanotwins) that occurs rapidly, even after few days at RT.

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Matériaux
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Dates et versions

hal-00785227 , version 1 (05-02-2013)

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Sébastien Allain, Frederic Danoix, Mohamed Gouné, Khalid Hoummada, Dominique Mangelinck. Static and dynamical ageing processes at room temperature in a Fe25Ni0.4C virgin martensite : effect of C redistribution at the nanoscale. Philosophical Magazine Letters, 2013, 93 (2), pp.68-76. ⟨10.1080/09500839.2012.742590⟩. ⟨hal-00785227⟩
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