en گروه شبیه سازی Materials Modeling and Simulation Research Paper Research Paper <div style="text-align: justify;">An experimental&ndash;numerical methodology was used in order to study the microstructural effects on stress state dependency of martensitic transformation kinetics in two different TRIP800 low alloy multiphase steels. Representative volume elements extracted from actual microstructure have been utilized for simulating the mechanical behavior of mentioned steels. The mechanical behavior for each constituent phases required in the model has been taken out from those reported in the literature. A stress invariant based transformation kinetics law has been used to predict the martensitic phase transformation during deformation. Crystallographic and thermodynamic theories of martensitic phase transformation have been utilized for estimating the constant parameters of the kinetics law, in a recently performed investigation, but the sensitivity of the transformation to the stress state remained as an adjusting parameter. The results of the current work show that the stress state sensitivity of martensitic phase transformation in the investigated steels is microstructure-dependent and the value of this parameter is almost equal to half of the bainite volume fraction. Therefore, the volume fraction of bainite in the low-alloy multiphase TRIP800 steels can be used as a first postulation for the value of the martensitic phase transformation sensitivity to the stress state and the microstructure based model previously developed for calculating the mechanical behavior of the TRIP800 steels can be utilized as a virtual design tool for development of TRIP steels having specific mechanical properties.</div> ,Mechanical properties,TRIP800 steels,Martensitic phase transformation,stress state sensitivity,Finite element model 109 123 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-2168-1&slc_lang=en&sid=1 F. Hosseinabadi fhossainabady@gmail.com 180031947532846009669 180031947532846009669 Yes Department of Metallurgy and Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran A. Rezaee-Bazzaz 180031947532846009670 180031947532846009670 No Department of Metallurgy and Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran M. Mazinani 180031947532846009671 180031947532846009671 No Department of Metallurgy and Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran B. Mohammad Sadeghi bmsadeghi@iust.ac.ir 180031947532846009672 180031947532846009672 No School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, Iran