Objectif
The influence of grain size reduction from the usual um sized to the nm-size range of austenitic-ferritic stainless steels is of great interest. It is especially the physical-mechanical and the corrosive properties that are improved by such a reduction of grain sizes.
The aim of this project is the targeted development of a method to produce this kind of nanocrystalline (nc) materials by a powder metallurgical route based on the pressure sintering of ultrafine powders.
Stainless steel (ss) powders in the grain size range of 10 - 100 nm are prepared by the impulse plasma channel method. The primary particles of such powders are either ferritic (a phase or austenitic g phase). The relative concentration of these phases determines the corrosive properties of the consolidated P/M product.
It is the purpose of this study to investigate the role of atomic diffusion on the phase transformation process in these nanocrystals in order to be able to tailor the phase ratio a/g after consolidation. For this purpose nc-ss powders will be coated. The diffusion profiles after heat treatment will be correlated with the resulting microstructure, especially the a/g phase ratio.
Thème(s)
Appel à propositions
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Data not availableCoordinateur
28717 Bremen
Allemagne