Coopetitive micro-mechanisms between recrystallization and transformation during/after dynamic strain-induced transformation in aluminum-containing low-carbon steel.

In this work, the coopetitive relationships among dynamic ferrite transformation, reverse ferrite transformation, and austenite recrystallization were investigated by using dynamic dilatometry, optical metallography, and electron backscattering diffraction in an aluminum-containing low-carbon steel subjected to hot compressions in the two-phase region. The microscopic mechanism of concurrent dynamic softening was studied based on the analysis of transformation crystallography. Moreover, this analysis method was used to discover the occurrence of reverse-transformation-induced recrystallization. In this microscopic mechanism, new austenite grains formed by reverse transformation can act as seeds for recrystallization. These paths for microstructural control in steels are not common, but they can be enabled by critical thermo-mechanical treatments combined with proper alloy design. [ABSTRACT FROM AUTHOR]