最近的进展在钢贝氏体转变的动力学.pdfVIP

Current Opinion in Solid State and Materials Science 8 (2004) 213–217 Recent progress: kinetics of the bainite transformation in steels Manabu Takahashi * Steel Research Laboratories, Nippon Steel Corporation, Shintomi 20-1, Futtsu, Chiba 293-8511, Japan Received 15 August 2004; received in revised form 19 August 2004; accepted 23 August 2004 Abstract There are two different approaches to model the kinetics of the bainite transformation. The diffusional growth model needs to adopt the solute drag effect, and a quantitative approach is proposed although the diffusion of substitutional alloying elements is not fully accepted experimentally. The nucleation-controlled model based on the displacive and diffusionless nature of the bainite trans- formation, combined with the kinetics of cementite formation in austenite and in ferrite as the simultaneous reactions. 2004 Elsevier Ltd. All rights reserved. Keywords: Bainite; Bainite transformation; Kinetics; T0 curve; Transformation stasis; Solute drag 1. Introduction ment conditions for a given production line. Even when steel contains substitutional alloying elements such as Si The bainite transformation is, as well recognized, one and Al, which are known to retard the formation of of the intensely discussed phenomena in steels. The cementite, the untransformed austenite could decom- major interest of the work is focused not only on the pose to cementite and ferrite during extended holding mechanism of the bainite transformation itself, but also at bainite transformation temperatures. It is, therefore, on a qu