Bainite is a two phase material composed of ferrite and cementite. It is an equilibrium structure in a carbon steel that has been isothermally transformed from the high temperature austenite phase at a temperature below the nose of the T-T-T curve. The photograph shows a Bainite produced by isothermal transformation of a Fe - 0.8 wt% C austenite at 316 C. The morphology of the Fe3C can be either needles or plates depending on the transformation temperature. The microstructure of the material is fine scale and needs an SEM photograph to be resolved.
From: Flinn and Trojan, "Engineering Materials and their Applications," Houghton Mifflin (1986)