Abstract:
Hypereutectic Al–Si alloys are used in components that require high resistance wear and corrosion,
good mechanical properties, low thermal expansion and
less density. The size and morphology of hard primary
silicon particles present in Al–Si alloys greatly influences
the mechanical properties. Addition of Mg leads to formation of intermetallic Mg2Si phases, which contributes
towards the properties of high silicon alloy as well as alters
the nature and quantity of primary silicon formed. The high
silicon alloy subjected to centrifugal casting leads to the
formation of functionally gradient material, which provides
variation in spatial and continuous distribution of primary
phases in a definite direction exhibiting selective properties
and functions within a component. The present study is to
evaluate the effect of Mg on solidification microstructures
of homogenous and functionally graded A390 aluminium
alloys. The addition of Mg from 3 to 5 % in A390 alloy
using Al–20Mg master alloy has shown a transformation
from primary silicon rich matrix to Mg2Si rich matrix.
Centrifugal casting shows the gradient distribution of primary silicon and Mg2Si phases towards the inner periphery
of the casting
