Creep strength boosted by a high-density of stable nanoprecipitates in highchromium steels
| Autor: | Javier Vivas, David De-Castro, Jonathan D. Poplawsky, Eberhard Altstadt, Martin Houska, Esteban Urones-Garrote, David San-Martín, Francisca G. Caballero, Marta Serrano, Carlos Capdevila |
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| Přispěvatelé: | Agencia Estatal de Investigación (España), Capdevila montes, Carlos, Ministerio de Economía, Industria y Competitividad (España) |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | European Journal of Materials (2023) |
| DOI: | 10.1080/26889277.2022.2118082 |
| Popis: | There is a need worldwide to develop materials for advanced power plants with steam temperatures of 700°C and above that will achieve long-term creep-rupture strength and low CO2 emissions. The creep resistance of actual 9-12Cr steels is not enough to fulfil the engineering requirements above 600°C. In this paper, the authors report their advances in the improvement of creep properties of this type of steels by the microstructural optimization through nano-precipitation using two methodologies. 1) Applying a high temperature austenitization cycle followed by an ausforming step (thermomechanical treatment, TMT) to G91 steel, to increase the martensite dislocation density and, thus, the number density of MX precipitates (M = V ,Nb; X = C ,N) but at the expense of deteriorating the ductility. 2) Compositional adjustments, guided by computational thermodynamics, combined with a conventional heat treatment (no TMT), to design novel steels with a good ductility while still possessing a high number density of MX precipitates, similar to the one obtained after the TMT in G91. The microstructures have been characterized by optical, scanning and transmission electron microscopy, EBSD and atom probe tomography. The creep behaviour at 700°C has been evaluated under a load of 200 N using small punch creep tests. The authors would like to thank James Burns for assistance in performing APT sample preparation and running the APT experiments. The authors are grateful for the dilatometer tests by Phase Transformation laboratory and for the SEM microscopy by the Microscopy Lab at CENIM-CSIC. This work contributes to the Joint Programme on Nuclear Materials (JPNM) of the European Energy Research Alliance (EERA). |
| Databáze: | OpenAIRE |
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