Strain-Induced Precipitation Behavior of a Nb–Ti–V Steel in the Austenite Phase Field

Authors

  • Matthias Nöhrer,

    Corresponding author
    1. Christian Doppler Laboratory for Early Stages of Precipitation, Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Franz-Josef-Straße 18, A-8700 Leoben, Austria
    • Christian Doppler Laboratory for Early Stages of Precipitation, Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Franz-Josef-Straße 18, A-8700 Leoben, Austria
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  • Sabine Zamberger,

    1. Voestalpine Stahl Donawitz GmbH & Co KG, Kerpelystraße 199, A-8700 Leoben, Austria
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  • Harald Leitner

    1. Christian Doppler Laboratory for Early Stages of Precipitation, Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Franz-Josef-Straße 18, A-8700 Leoben, Austria
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Abstract

The precipitation behavior of a Nb (0.041 wt%), V (0.11 wt%), and Ti (0.018 wt%) micro-alloyed steel influenced by a deformation process in the austenite region has been investigated by transmission electron microscopy and atom probe. After solution annealing at 1250°C, nearly the entire Nb and V amount is in solid solution. Ti does not go into in solid solution and stays stable as TiN precipitates. During the cooling process to deformation temperature, these TiN precipitates act as nucleation sites for Nb and V. Precipitates with a TiN rich core and a V-rich shell are formed. Nb is homogenously distributed over the precipitate. After deformation, strain induced precipitates occur, which consist mainly of Nb, V, and only a little Ti. Smaller strain induced precipitates have a higher N-content than C, with growth the C-content increases.

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