Theory and Modeling of Phase Transformations under Stress in Steel

摘要

Thermodynamic prediction of the increment of the formation temperature of proeutectoid ferrite by appliedstress is nearly consistent with the wxperfimental data.Kinetics models for ferrite,pearlite and bainite transformations can be shown as modified Johnson-Mehl-Avrami equation in which parameter b() varies with the level of applied stress.The effects of tensile and compressive stresses on enhancement of the ferrite/pearlite and bainite transformations are discussed,The necessity and approach of modification of additivity hypothesis are introduced and the results from modified equation in which some parameters are obtained by rfegression of two experimental results or taken from TTT and CCT diagrams of a cerftain steel are superior than that from Scheil’s eqation.Thermodynamic calculation of Ms and nucleation kinetics equations of martensitic transformation under stress are suggested.Modeling of phase trasformations under stress in ferrous alloys is briefly