31-08-2012, 04:21 PM
Micromechanical Modeling of Ferrite/Pearlite steels
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ABSTRACT
Composite or heterogeneous materials on the level of the
individual phases that constitute these materials. In this
project micromechanical structure of ferritic/pearlitic
steels was modeled by two methods. First SHA model
(stacked hexagonal array) and second the real
microstructure of the steels. FE analysis was performed
to investigate the influence of some parameters such as
volume fraction and aspect ratio of the second phase on
deformation behavior and also macroscopic and
microscopic responses to tension and shear. The stressstrain
curves from FE analysis of both models and
experimental results obtained from some papers were
similar. Afterward, a comparison between averages
strains in different types of steel were performed that
shows a rise by increasing pearlite volume fraction in
steels.
Introduction
The main aim of micromechanics is to predict the
properties of the materials by considering the
properties of their constituent phases. By
controlling microstructure an optimum mechanical
properties can be achieved for structural materials.
For studying the effect of morphology of second
phase on stress-strain curve, FE analysis was
performed preliminary [3, 4]. The Stacked
Hexagonal-Array (SHA model) was proposed by
Tvegaard [2] and widely used after that for twophase
material. Ishikawa et al. (2000) [1] reported
the axisymmetric Voronoi cell model to estimate
the behavior of ferrite-pearlite steels.
Conclusions
The first section present the SHA model and
microstructure model of ferrite/pearlite steels in
applying tension. The stress-strain curves from both
models show good matching with experiments [1].This
verifies the accuracy of both methods of modeling. In
the second section a simple shear was created. Average
strains in the steels with different pearlite volume
fraction, shows a rise by increasing volume fraction.
This point can be very useful in metal cutting.