Template for abstract of MCWASP 2015
Macroscopic modeling of semisolid deformation for considering the band
segregation induced by shear deformation
S. Morita1, H. Yasuda1, T. Nagira2, M. Yoshiya2, C. Gourlay3, A. Sugiyama4
1
Department of Materials Science and Engineering, Osaka University
Department of Adaptive Machine Systems, Osaka University
3
Department of Materials, Imperial College, U.K.
4
Osaka Sangyo University
2
Recently, in-situ observation was carried out to observe shear deformation of semi-solid Fe-2C steel by
using synchrotron X-ray radiography. Samples with globular morphology and effective solid fractions of
55-65% were deformed at a rate of ~10-3 s-1. Deformation was predominantly controlled by the
rearrangement of globules. The solid particles were pushed each other and the rearrangement caused the
lower solid fraction region in the shear deformation. Thus, the interaction between the solid particles is a
key issue for understanding the segregation induced by the shear deformation. On the basis of the in-situ
observation, a macroscopic model is introduced to simulate the deformation and the segregation. In this
model, the solid particles are treated as a non-Newtonian fluid. The governing equations using the
two-phase flow model are given by the Navier-Stokes equations and mass conservation equations for
liquid and solid.
¶
¶
¶P
¶ l
(1)
r flu i + r
fl u iu j = -fl
+
t - Fsl
¶t
¶x j
¶x i ¶x j ij i
( )
r
(
)
(
)
(2)
¶fl
¶
+
fu =0
¶t ¶x i l i
(3)
¶fs
¶
+
f v =0
¶t ¶x i s i
(4)
f l + fs = 1
(5)
¶
¶
¶P
¶ s
fs v i ) + r
fs v i v j = -fs
+
t + Fsl
(
¶t
¶x j
¶x i ¶x j ij i
( )
( )
Here, ui: velocity of liquid (i=1,2,3), vi: velocity of solid, fs: solid fraction, fl: liquid fraction, P: pressure,
τij: stress tensor, Fsli: Interaction between liquid and solid. τsij represents the interaction between the solid
particles, which can cause the segregation. When τsij are set so that the normal stress is induced by the
simple shear (like s11 = Ce 21 ), the segregation of solid phase can occur. Instability to shear deformation
arises in semisolid by introducing the normal stress.
…
…
…
…
This paper shows the basic idea of the proposed model and discusses feasibility of the model for
simulating the segregation induced by the shear deformation.
Template for abstract of MCWASP 2015
Information
Speaker
Hideyuki YASUDA
Title
Dr.
Affiliation
Department of Materials Science and Engineering,
Kyoto University
e-mail
yasuda.hideyuki.6s@kyoto-u.ac.jp
Tel
+81-75-753-3339
Fax
+81-75-753-3339
Presentation preference
Oral / Poster / Either one will be fine
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Solidification processing of metallic alloys and non-metallic materials.
Shape casting (sand casting, HPD casting, thixocasting, rheocasting,
lost foam,..), continuous casting.
Welding and soldering processes.
Treatment after casting (heat treatment, machining, shot peening).
Novel process techniques.
Green technology in casting, solidification and welding (recycling
etc…)
Processing / structure / property relations.
High temperature/ mushy zone properties.
Properties of mold and core materials (thermal conductivity, specific
heat, density, mechanical properties).
Nucleation, grain refinement, inoculation techniques.
Microstructure evolution, columnar-to-equiaxed Transition,
globular-to-dendritic transition.
Micro- and macrosegregation, thermodynamic of solidification.
Stress and deformation, hot tearing, macro-shrinkage, and porosity.
In-situ observations of solidification phenomena and comparison with
predictions.
Numerical techniques for solidification modeling (FEM, FVM, DEM,
LB, …)
High performance computing, parallelization strategies.
Others