Heterogeneous deformation and recrystallisation of iron base oxide dispersion strengthened PM2000 alloy

Abstract

The recrystallisation behaviour of PM2000 oxide dispersion strengthened ferritic alloy has been investigated for tube specimens which had been cold deformed after extrusion. The evolution of the recrystallisation temperature, defined as the minimum temperature at which the specimen begins to recrystallise, has been studied in detail as a function of the level of deformation. The microstructure was characterised using optical and transmission electron microscopy, together with microhardness measurements, and local texture measurements obtained using the electron backscattering pattern technique. The results can be interpreted if it is assumed that any procedure that produces a heterogeneous microstructure, stimulates recrystallisation. In this sense, larger strain gradients lead to more refined and more isotropic grain structures. The way in which these results can be exploited for commercial applications is discussed.