A Unique Method to Determine Ferrite and Martensite Phase Stress Strain Curve for Manufacturing Process

Abstract

Finite element (FE) methods have been extensively used to simulate the effects of material's microstructure during the machining processes. However, determination of the individual microstructure phase stress strain curves is experimentally intensive and difficult to measure. Furthermore, these curves were also affected by heat treatment processes, chemical composition, and the percentage of individual microstructure phases. The objective of this paper is to develop and validate the Micromechanical Adaptive Iteration Algorithm to calculate the individual ferrite and martensite plastic behavior for dual phase (DP) steel. This method requires a minimum of three experimental stress-strain curves from the same material with three different martensite volume fractions (Vm). Two of the stress-strain curves with different Vm is required to initialize the iteration algorithm to predict the individual plastic behavior of ferrite and martensite. The third stress strain curve was used to validate the plastic behavior of individual ferrite and martensite for the given DP steel. Following on from here, the proposed algorithm was validated with two different grades of DP steel with 0.088%C and 0.1%C. Validation results shows that the approach has consistent prediction capabilities and the maximum difference observed between predicted and experimental results was 6.5%. The simulated results also shows that the degree of strain partitioning between ferrite and martensite decreases with increasing volumetric fraction of martensite (Vm).