The Influence of Critical Points and Structure and Microstructural Evolution in Iron Rich Fe-Si Alloys

Raviprasad, K and Chattopadhyay, K (1993) The Influence of Critical Points and Structure and Microstructural Evolution in Iron Rich Fe-Si Alloys. In: Acta Metallurgica et Materialia, 41 (2). pp. 609-624.

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Abstract

The evolution of microstructure in Fe-8.7 to 14.2 at.% Si alloys in the neighbourhood of higher order transition lines has been investigated. Systematics of various features of the Fe-Si phase diagram, highlighting the multicritical points, have been presented. The possible influence of these critical points on the kinetic pathways for the microstructural evolution has been discussed and compared with experimental results. It is shown that below the metastable tricritical point the alloy undergoes continuous ordering and a conditional spinodal followed by the renucleation of B2 phase in the $DO_3$ matrix. The latter process leads to the anomalous contrast in the B2 superlattice darkfield images. It is also shown that above the metastable (extrapolated) higher order $B2 \rightarrow DO_3$ transition line a small domain exists in the two phase field where decomposition to two phase B2 + $DO_3$ takes place by classical nucleation of fine $DO_3$ domains in B2 matrix. No evidence for $DO_3$ ordering could be obtained in alloy containing less than 11 at.% Si

Item Type: Journal Article Copyright of this article belongs to Elsevier. Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) 10 Aug 2006 19 Sep 2010 04:30 http://eprints.iisc.ernet.in/id/eprint/7988