Numerical Modeling Of Centrifugal Casting Of Functionally-Graded Aluminum Matrix Composites Reinforced With Diboride Particles.

Abstract

Surface modification and coating techniques are widely used to improve tribological
properties of metallic materials for a wide range of manufacturing, transportation, defense, and
consumer industries. However, in all these techniques a surface treatment is applied after the
part has been fabricated, and this adds significantly to the overall costs. An alternative, costeffect
method has been, proposed via functionalization of aluminum matrix composites
uniformly reinforced with hard particles. A larger volume fraction of those particles can be
attained near the wear surface via centrifugal casting,. The volume fraction of the heavier
borides is controlled by inertial forces upon centrifugal processing the semisolid composite.
In this study, boride particles are modeled as spherical particles subject to a drag force in a Stoke
flow in the liquid aluminum matrix. This equation of motion for the particles under the applied
centrifugal forces is solved numerically assuming a gaussian diameter size distribution with a
spatial uniform random distribution of particles in the sample. The effect of temperature on the
viscosity is also considered by solving the energy equation. From parametric studies in the
numerical model, it is possible to better understand and control the experimental conditions to
obtain an appropriate functionally-graded aluminum matrix for high wear resistance
applications.