Precipitation sensitivity to alloy composition in Fe-Cr-Mn austenitic steels developed for reduced activation for fusion application
Special austenitic steels are being designed in which alloying elements like Mo, Nb, and Ni are replaced with Mn, W, V, Ti, and/or Ta to reduce the long-term radioactivity induced by fusion reactor irradiation. However, the new steels still need to have properties otherwise similar to commercial steels like type 316. Precipitation strongly affects strength and radiation-resistance in austenitic steels during irradiation at 400--600/degree/C, and precipitation is also usually quite sensitive to alloy composition. The initial stage of development was to define a base Fe-Cr-Mn-C composition that formed stable austenite after annealing and cold-working, and resisted recovery or excessive formation of coarse carbide and intermetallic phases during elevated temperature annealing. These studies produced a Fe-12Cr-20Mn-0.25C base alloy. The next stage was to add the minor alloying elements W, Ti, V, P, and B for more strength and radiation-resistance. One of the goals was to produce fine MC precipitation behavior similar to the Ti-modified Fe-Cr-Ni prime candidate alloy (PCA). Additions of Ti+V+P+B produced fine MC precipitation along network dislocations and recovery/recrystallization resistance in 20% cold worked material aged at 800/degree/C for 166h, whereas W, Ti, W+Ti, or Ti+P+B additions did not. Addition of W+Ti+V+P+B also produced fine MC, but caused some sigma phase formation and more recrystallization as well. 29 refs., 14 figs., 9 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6580234
- Report Number(s):
- CONF-880613-24; ON: DE89003367
- Resource Relation:
- Conference: 14. international symposium on effects of radiation on materials, Andover, MA, United States, 27 Jun 1988; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
AUSTENITIC STEELS
METALLURGICAL EFFECTS
ANNEALING
CARBIDES
CHEMICAL COMPOSITION
COLD WORKING
MICROSTRUCTURE
PHASE TRANSFORMATIONS
PRECIPITATION
RADIATION EFFECTS
RECRYSTALLIZATION
ALLOYS
CARBON COMPOUNDS
CRYSTAL STRUCTURE
FABRICATION
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS WORKING
SEPARATION PROCESSES
STEELS
700209* - Fusion Power Plant Technology- Component Development & Materials Testing
360102 - Metals & Alloys- Structure & Phase Studies
360103 - Metals & Alloys- Mechanical Properties