Latest advance of bainite phase transformation theory in steels

The main research findings on the field of hainite phase transformation studied in Inner Mongolia University of Science and Technology in recent years were generalized,which shows that transition is the principle character of bainite phase transformation.The new definition of bainite and bainite phase transformation were put forward.It is considered that the past calculation of thermodynamics is inaccurate and the driving force of bainite phase transformation is about 905 J/mol.The shearing-diffusing mechanics of bainite phase transformation integrated in a systematic way was proposed and the crystal nucleus of bainite phase transformation is not eutectoid decomposition product but single-phase bainite ferrite.The bainite ferrite nucleates in carbon-poor austenite area and the γ→α transform is diffusionless,whose nucleation and growth are not by shear transformation but by heat activation transition of interface substitution stoms.The bainite carbide nucleates at the interface of γ/α and grows into austenite and ferrite,and at last the carbide is enclosed by ferrite,which is diffusion transformation by the form of atom heat activation transition.