In-Situ Observation of Texture Changes during Phase Transformations in Ultra-Low-Carbon Steel

Texture changes during the α(bcc)-γ(fcc) phase transformation in ultra-low-carbon (ULC) steel were investigated in situ by neutron diffraction, making use of a vacuum furnace. The initial texture is a typical bcc rolling texture. Upon heating above 500 °C, it recrystallizes, and above 900 °C, it transforms into an fcc texture with (111) fcc pole figures resembling (110) bcc and (110) fcc resembling (111) bcc. Upon cooling, the reverse transformation produces a texture that is close to the initial one, documenting a texture memory. Modeling the texture changes with the Kurdjumov–Sachs (KS), Nishiyama–Wassermann (NW), and Bain relationships reproduces the correct texture patterns but considerably weaker texture strengths, indicating that in the experimental case, variant selection occurs during both the forward and reverse transformations.