Abstract
Stir casting is an economical method to produce aluminum matrix composites
(AMCs). In this work, stir casting was used to produce AA6061/15wt. % TiC AMCs. An
empirical relationship was developed to predict the effect of stir casting parameters on the
ultimate tensile strength (UTS) of AA6061/TiC AMCs. A central composite rotatable design
consisting of four factors and five levels was used to minimize the number of experiments i.e.
castings. The factors considered were stirrer speed, stirring time, blade angle and casting
temperature. The effect of those factors on the UTS of AA6061/TiC AMCs was derived
using the developed empirical relationship and elucidated using microstructural
characterization. Each factor significantly influenced the UTS. A higher or lower values of
those factors resulted in poor tensile strength. The variation in the UTS was attributed to
porosity content, cluster formation, segregation of TiC particles at the grain boundaries and
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homogenous distribution in the aluminum matrix. The UTS was high when the porosity
content was low and the distribution was homogenous. The present work concludes that a
careful selection and control of stir casting parameters are necessary to reduce porosity
content and obtain uniform distribution to improve the load bearing capacity of the
AA6061/TiC AMCs.