Analysis of Work Hardening Behavior in Ferrite-Martensite Dual-phase Steels Using Micro-grid Method

To clarify the contribution of martensite increase to work-hardening during transformation-induced plasticity (TRIP), changes in local strain distribution with tensile deformation were investigated for dual-phase steels different volume fractions ferrite using precise marker method. Particular attention was paid and stress bearing by deformation. The method is especially useful analysis multiphase materials. Three types 25%, 50%, 75% subjected at several stages important results are as follows: (1) a large fraction martensite, plastic overall from beginning deformation, (2) difference increases through both 25% 50% martensitic steels. Using constitutive equations stress-strain response, distributions each phase translated into distributions. Then, response numerically estimated applying general rule mixtures average values stress, compared experimental results. relationship between controlled transformation behavior TRIP steel also discussed.