| EPSRC Reference: |
GR/S86501/01 |
| Title: |
NSF: A Novel Approach to Develop New Steel Microstructures by Controlling Carbon Partitioning in Martensite |
| Principal Investigator: |
Edmonds, Professor DV |
| Other Investigators: |
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| Researcher Co-Investigators: |
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| Project Partners: |
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| Department: |
Institute of Materials Research |
| Organisation: |
University of Leeds |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 February 2004 |
Ends: |
31 January 2007 |
Value (£): |
236,357
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| EPSRC Research Topic Classifications: |
| Materials Characterisation |
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Summary on Grant Application Form |
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The purpose of this joint programme of international collaboration is to prove the potential for developing new steels and microstructures by a novel steel heat treatment route, relevant to a broad range of steel grades, from fundamental transformation theory. This innovative process has been termed quenching and partitioning or Q&P, and is based on a new thermodynamic model that has been developed to understand carbon partitioning between martensite and retained austenite. (Carbon partitioning from martensite is not usually considered, because of carbide precipitation reactions that usually occur during tempering, but alloying approaches can be implemented to suppress these competing reactions.) The model to describe the endpoint of partitioning is new, and defines the conditions under which carbon reaches a uniform chemical potential in the two phases, while the martensite/austenite interface remains stationary (implying complete immobility of iron atoms). The model indicates that substantial carbon enrichment of austenite may be achieved by careful control of the martensite transformation and subsequent partitioning behavior, and some encouraging preliminary experimental results of new heat treatment schedules based upon the key elements of this constrained paraequilibrium or CPE, have been obtained. A number of important potential applications for this new concept can be identified, along with fundamental implications related to the mechanism of bainite transformation in steels. In the first part of the programme, the research will concentrate on two parallel aspects of microstructure development, one in TRIP-assisted sheet steel products (demanding strength and formability), and the other in much higher strength bar steels (including spring steels demanding strength and toughness, and carburized gears and bearings requiring high hardness and rolling contact fatigue resistance).The team at the Colorado School of Mines will focus their technical efforts on understanding key aspects of microstructure development and alloy design/processing response. The Brazilian partner, at the Pontificia Universidade Catolica, Rio de Janeiro, will model quantitatively various aspects critical to understanding the carbon partitioning involved in the heat treatment process. The contribution of the UK partner, through this proposal, will be microstructural characterisation, mainly by high-resolution microanalytical electron microscopy techniques, with an emphasis on studying the carbide precipitation reactions, particularly of transition carbides, and their suppression in martensite.
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
| Summary |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.leeds.ac.uk |