Measurement of volume fraction of epsilon martensite in Fe-Mn based alloys

Abstract

In this work, we propose a new way of measuring the volume fraction of epsilon martensite in Fe-Mn based alloys. Since the specific volume of epsilon, depending on alloy composition, is smaller than that of , volume expansion (VE) takes place on epsilon --> reverse transformation. The amount of the volume expansion is proportional to the product of specific volume difference times the volume fraction of E martensite, therefore, the measurement of two former values leads to the volume fraction. Two Fe-Mn based alloys are taken as examples, an Fe-21Mn and an Fe-32Mn-6Si alloys which undergo --> epsilon on cooling and by cold rolling, respectively. Thus, former alloy has isotropic epsilon, the latter has anisotropic epsilon. (C) 2004 Elsevier B.V. All rights reserved.