ON THE THERMODYNAMIC STABILITY OF RETAINED AUSTENITE IN 4340-STEEL

Citation
Gn. Haidemenopoulos et An. Vasilakos, ON THE THERMODYNAMIC STABILITY OF RETAINED AUSTENITE IN 4340-STEEL, Journal of alloys and compounds, 247, 1997, pp. 128-133
Citations number
18
Categorie Soggetti
Chemistry Physical","Metallurgy & Metallurigical Engineering","Material Science
ISSN journal
09258388
Volume
247
Year of publication
1997
Pages
128 - 133
Database
ISI
SICI code
0925-8388(1997)247:<128:OTTSOR>2.0.ZU;2-8
Abstract
The effect of retained austenite on the mechanical behavior of quenche d and tempered steels depends on its thermodynamic stability against m echanically-induced martensitic transformation during loading. In this work, the stability of retained austenite is characterized by the M(s )(sigma) temperature and experimentally determined values of the M(s)( sigma) temperature are compared with model predictions. The comparison suggests that significant carbon stabilization of the retained austen ite occurs during tempering for both, high and low temperature, austen itizing treatments employed. In addition, it appears that the assumpti on of a fully-biased rather than a fully-random distribution of nuclea tion-site potencies is in better agreement with the observed experimen tal behavior. Finally, the stress state dependence of the retained aus tenite stability could account for the mechanical behavior variation r eported in literature.