An Investigation into the Cause of Inhomogeneous Distributions of Aluminium Nitrides in Silicon Steels

Two electrical steels containing 0.014 wt.% aluminium and 0.013-0.014 wt.% nitrogen were characterised to determine the operating recrystallisation mechanism following different heat treatment schedules. It was found that the operating recrystallisation mechanism depended on grain orientation with sub-grain coalescence and low-angle boundary movement occurring for {111} -oriented grains and high-angle boundary movement occurring for {110} -oriented grains in the narrow deformed bands. In addition, the number density of AlN precipitates (characterised using TEM) was larger in the {111}-oriented grains compared to the {110}-oriented grains. The higher number density of precipitates was due to the presence of dislocations remaining after recrystallisation. (C) 2002 Elsevier Science B.V. All rights reserved.