Effect of deformation temperature on niobium clustering, precipitation and austenite recrystallisation in a Nb-Ti microalloyed steel

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:581

Article

Kostryzhev, Andrii G.¹  Al Shahrani, Abdullah¹  Zhu, Chen^2,3  Ringer, Simon P.^2,3  Pereloma, Elena V.¹ 

[1] Univ Wollongong, Sch Mech Mat & Mechatron Engn, Wollongong, NSW 2522, Australia

[2] Univ Sydney, Australian Ctr Microscopy & Microanal, Sydney, NSW 2006, Australia

[3] Univ Sydney, Sch Aerosp Mech & Mechatron Engn, Sydney, NSW 2006, Australia

关键词: Microalloyed steel;    Nb precipitation kinetics;    Austenite recrystallisation kinetics;   

DOI  :  10.1016/j.msea.2013.05.068

来源: Elsevier

【 摘 要 】

The effect of deformation temperature on Nb solute clustering, precipitation and the kinetics of austenite reaystallisation were studied in a steel containing 0.081C-0.021Ti-0.064 Nb (wt%). Thermo-mechanical processing was carried out using a Gleeble 3500 simulator. The austenite microstructure was studied using a combination of optical microscopy, transmission electron microscopy, and atom probe microscopy, enabling a careful characterisation of grain size, as well as Nb-rich clustering and precipitation processes. A correlation between the austenite recrystallisation kinetics and the chemistry, size and number density of Nb-rich solute atom clusters, and NbTi(C,N) precipitates was established via the austenite deformation temperature. Specifically, we have determined thresholds for the onset of recrystallisation: for deformation levels above 75% and temperatures above 825 degrees C, Nb atom clusters <8 nm effectively suppressed austenite recrystallisation. (C) 2013 Elsevier B.V. All rights reserved.

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