Barrier-free heterogeneous grain nucleation in polycrystalline materials: The austenite to ferrite phase transformation in steel

✍ Scribed by N.H. van Dijk; S.E. Offerman; J. Sietsma; S. van der Zwaag

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 310 KB
• Volume: 55
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2007.04.013

✦ Synopsis

The process of grain formation during structural solid-state phase transformations has commonly been analysed in terms of the classical nucleation theory. In polycrystalline materials a new phase generally forms at grain boundaries in the parent phase microstructure. Under certain conditions the net interfacial energy to form a new phase can be relatively small due to the release of grain boundary energy from the parent phase. The nucleation process is then governed by cluster dynamics. We propose a simple model to predict the cross-over between different heterogeneous nucleation regimes and apply it to recent synchrotron X-ray diffraction experiments on ferrite nucleation in steel.