Compositional analysis on the reverted austenite and tempered martensite in a Ti-stabilized supermartensitic stainless steel: Segregation, partitioning and carbide precipitation
| Autor: | J. Rodriguez, G.A. Faria, Antonio J. Ramirez, Jonathan D. Poplawsky, João Pedro Oliveira, J.D. Escobar, Paulo Roberto Mei, S. Suresh Babu, Camilo A.F. Salvador |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Austenite Materials science Precipitation (chemistry) Mechanical Engineering Metallurgy Energy-dispersive X-ray spectroscopy 02 engineering and technology Atom probe 021001 nanoscience & nanotechnology 01 natural sciences Isothermal process Carbide law.invention Mechanics of Materials law Martensite 0103 physical sciences lcsh:TA401-492 General Materials Science lcsh:Materials of engineering and construction. Mechanics of materials Tempering 0210 nano-technology |
| Zdroj: | Materials & Design, Vol 140, Iss, Pp 95-105 (2018) |
| ISSN: | 0264-1275 |
| Popis: | Controlling the amount of reverted austenite at room temperature allows for tailoring of mechanical properties in supermartensitic stainless steels. The austenite reversion and stabilization occurs during inter-critical tempering through partitioning of austenite-stabilizing elements. The degree of partitioning greatly depends on the reversion temperature, which dictates the local equilibrium conditions. Atom probe tomography and energy dispersive spectroscopy in transmission electron microscopy were used to study the austenite reversion mechanism in terms of the elemental distribution of austenite-stabilizing, ferrite-stabilizing and carbide forming elements. Synchrotron X-ray diffraction confirmed that the austenite equilibrium phase fraction was reached after 2.5 h of isothermal reversion at 625 °C, allowing for direct comparison with thermodynamic and kinetic calculations. However, such soaking time was not enough to produce compositional homogenization in the reverted austenite. The austenite reversion and stabilization mechanism was related mainly to strong partitioning of Ni. Negligible partitioning of Cr, Mo, Si and Ti were observed. Instead, these elements were strongly segregated at the reverted austenite/martensite interfaces. Carbon and Ti played a secondary role in the austenite stabilization through the precipitation of nano-sized Ti (C,N) with partial substitution of Ti by Mo. Virtually carbon-free austenite and martensite were observed away from the interfaces and precipitates. Keywords: Atom probe tomography, Austenite reversion, Isothermal tempering treatments, Synchrotron diffraction |
| Databáze: | OpenAIRE |
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