Effects of prior plastic deformation on the distribution and morphology of AlN precipitates in α iron

Abstract

Electron microscope study has been made on the morphology of AlN particles in early stages of precipitation in a deformed Fe-0.04% Al-0.005% N alloy. Drastic effects of deformation prior to the precipitation annealing upon the precipitate morphology have been found. Prior tensile deformation of 5% results in a tenfold increase in the density, along with a remarkable refinement, of the precipitate particles. Diffraction condition has been varied widely to obtain information on the coherency strain around fine precipitates. The effects of the prior deformation are satisfactorily explained in terms of deformation-induced prismatic loops which act as nucleation sites for AlN.