Mechanisms for microstructural evolution of FeSiCrNi high silicon steel subjected to thermomechanical processing

Fe-6.5 wt% Si high silicon steel alloy presents excellent soft magnetic performances, but a poor plasticity limits its industrial application seriously. In this work, a novel FeSiCrNi alloy with the chemical composition of Fe6.5Si-2Cr-12Ni (wt%) is designed and subjected to thermomechanical processing including local canning compression at room temperature and annealing at elevated temperatures. It is observed that microstructures of FeSiCrNi specimens with a compression degree of 70 % are dominated by dislocation cells. The microstructural evolution is transformed from static recovery to static recrystallization when FeSiCrNi specimens are annealed from 400 to 700 degrees C. Grains with high strain energy are successively nucleated via the integration of subgrain boundaries at 600 degrees C and a pronounced growth of recrystallized grains occurs at 700 degrees C. In particular, microtextures of the FeSiCrNi alloy essentially consist of gamma-fiber ({11 1}IIND) and lambda-fiber ({10 0}IIND) textures during recovery and recrystallization. The intensity of lambda-fiber texture is weakened with increasing annealing temperature, while the intensity of gamma-fiber which is composed of {111} (112) and {111} (110) textures is strengthened. The intensity of {111} (112) texture within the recrystallized FeSiCrNi grains reaches the maximum value at 700 degrees C.