Moessbauer Analysis of Low-Temperature Bainite
- Departament de Fisica Aplicada, Escola Politecnica Superior de Castelldefels, Universitat Politecnica de Catalunya, Avda. del Canal Olimpic s/n, 08860-Castelldefels (Spain)
- Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, ESAB, Urgell 187, 08036-Barcelona (Spain)
- Departamento de Metalurgia Fisica. CENIM-CSIC, Avda. Gregorio del Amo 8, 28040-Madrid (Spain)
- Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge (United Kingdom)
Low-temperature bainite, obtained by the transformation of austenite at temperatures as low as 200 deg. C for times as large as several days, has been reported to have extraordinary mechanical properties including the highest reported hardness of any bainitic steel. The unusual properties are a consequence of the fine scale of the microstructure, which contains bainite plates with thickness in the range 20-40 nm. The microstructure also contains carbon-enriched retained austenite which contributes to the properties via a number of mechanisms. In this work, the microstructure of a high carbon bainitic steel with Si to avoid cementite precipitation and Co to accelerate the transformation has been studied using Moessbauer spectroscopy for a series of samples transformed isothermally at 200 deg. C for time periods of 26, 34 and 96 hours. The total austenite content is almost identical ({approx}13 wt%) for these samples although the carbon concentrations of the phases differ as a function of transformation time. The austenite increases its carbon content from 5.4 atomic % after 26 h transformation to 6.3 at.% after 96 h, while the final bainitic phase retains about 2.2 at.% of C. These results are consistent with data obtained using atom probe tomography for samples transformed isothermally for 12 days.
- OSTI ID:
- 20722154
- Journal Information:
- AIP Conference Proceedings, Vol. 765, Issue 1; Conference: International symposium on the industrial applications of the Moessbauer effect, Madrid (Spain), 4-8 Oct 2004; Other Information: DOI: 10.1063/1.1923678; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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