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Enhancement of strength and ductility in ultrafine-grained T91 steel through thermomechanical treatments.
- Source :
- Journal of Materials Science; Nov2013, Vol. 48 Issue 21, p7360-7373, 14p, 3 Black and White Photographs, 1 Diagram, 4 Charts, 6 Graphs
- Publication Year :
- 2013
-
Abstract
- We report on the microstructure and mechanical properties of T91 alloy subjected to different thermomechanical treatments (TMTs). Equal channel angular extrusion (ECAE) was performed at 23, 300, 625, and 700 °C. Mechanical strength of T91 alloy is enhanced after cold-ECAE at the expense of ductility. In comparison, the hot-ECAE process leads to less pronounced hardening but retention of ductility and work hardening ability. Microstructure analyses reveal that cold-ECAE has significantly reduced the average grain size, while hot-ECAE is more effective to refine and uniformly redistribute carbide nanoprecipitates. Post-ECAE annealing (500 °C/10 h) leads to reprecipitation of large carbide particles in cold-ECAE processed alloy, whereas the hot-ECAEed specimens retain smaller nanoscale carbide precipitates and uniform microstructure. A mechanism is proposed to explain the influence of TMT on the evolution of precipitates. Strengthening of T91 alloy is discussed through a modified model that considers the effects of dislocation density, grain size, and precipitation hardening. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00222461
- Volume :
- 48
- Issue :
- 21
- Database :
- Complementary Index
- Journal :
- Journal of Materials Science
- Publication Type :
- Academic Journal
- Accession number :
- 89702932
- Full Text :
- https://doi.org/10.1007/s10853-013-7522-3