Effect of Strain Heterogeneity on Recrystallisation of Pm2000

The recrystallisation behaviour of PM2000 oxide dispersion strengthened ferritic alloy has been investigated for samples which were cold deformed after extrusion. The evolution of the recrystallisation temperature TR, defined as the minimum temperature at which the sample begins to recrystallise, has been studied in detail as a function of the level of deformation. The microstructure was characterised using transmission electron and optical microscopy, together with microhardness measurements. The results can be interpreted if it is assumed that anything which makes the microstructure heterogeneous, 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 are discussed.