STUDIES ON CONTROL OF MICA PARTICLE DISTRIBUTION IN ALUMINIUM ALLOY-MICA PARTICULATE COMPOSITES.

Abstract

A mechanically stirred Al-4wt% Cu-1.5% Mg-mica particulate composite was solidified in a variety of moulds

under different heat flow conditions and particles (41μm diameter and 3.8μm thick) in suspension were observed.

There was floatation of mica particles before and during solidification resulting in a cast structure with non-uniform

distribution of dispersed mica particles as well as mica-segregated and denuded zones.

The use of bottom chilling and/or low pouring temperatures were found to minimize mica segregations in relatively

thick castings. A homogeneous distribution of mica particles was found to be possible in thin castings of about 12.5

to 3mm. The composite is a good candidate for tribological applications.