The Microstructural Evolution of the Coexistence of Spinodal Decomposition and Ordering in Fe-23al Alloy during Aging
نویسندگان
چکیده
Article history: Received: 28.11.2012. Received in revised form: 04.01.2013. Accepted: 15.01.2013. The microstructural evolution of the coexistence of spinodal decomposition and ordering is characterized by metallographic microscopy and transmission electron microscopy in aged Fe-23Al (i.e. Fe-23at%Al) alloy. This paper discusses a phase transition mechanism of the microstructure evolution. The obtained results indicate that the asquenched Fe-23Al alloys with equiaxed grain size of about 500μm comprise two kinds of the ordered phase in nano-scale, i.e., B2-FeAl and DO3-Fe3Al phases. The average size of B2-FeAl ordering phases is about 15nm, while the size of DO3-Fe3Al ordering phases is extreme fine in the asquenched Fe-23Al alloys. The as-quenched Fe-23Al alloy presents characteristics of the coexistence of spinodal decomposition and ordering during the subsequent ageing at 565°C and 520°C. The domain size of B2-FeAl ordered phase rapidly increases while the one of DO3-Fe3Al ordered phase slowly develops with the increase in aging time/with increased ageing time. A conclusion is reached that the coarsening process of both B2FeAl and DO3-Fe3Al ordered phase is controlled by the spinodal decomposition mechanism.
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