Precipitation and recrystallization in an Al-1-8%Mn alloy

Abstract

The recrystallization behaviour of cold-rolled supersaturated AI-I.8%Mn has been investigated. In this alloy coarse intermetallic constituent particles remaining from casting exist, after light annealing, in a matrix stabilized by copious precipitation on subgrain boundaries. Subsequently, recrystallization occurs only in the vicinity of the coarse particles. Annealing experiments performed in the HVEM showed that a precipitate-free zone developed around the coarse particles by precipitate dissolution, thus allowing nucleation by subgrain growth. The growth of such nuclei was not prevented by the surviving fine precipitates. Solute profiles of various stages of this process were obtained by an X-ray energy dispersive spectrometer fitted to a STEM which gave evidence of rapid Mn diffusion along subgrain boundaries. These results are compared with recent theoretical work concerning the effect of fine particle dispersions on recrystallization.