Investigation and measurement of porosity in Al + 4.5Cu/6wt%TiB2 in situ composite: optimization and statistical modelling

Abstract

Present work investigates the adequacy of stir casting technique using mixed salt route method to fabricate in situ Al-4.5Cu-6wt%TiB2 composites and further the variation of porosity present in cast composite with varying pouring temperature, pouring time and different types of gating systems. The casting was found to be effective and economical for top gating system amongst rest of the gating design. The microstructural analysis of cast composite was carried out to determine the physical morphology and distribution of the TiB2 and Al2Cu phases in the matrix with the help of scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis of cast composite shows the formation of TiB2 particles in the absence of intermetallic, hard and brittle compound Al3Ti. Microstructural characterization was tandem with optical and high-resolution transmission electron microscopy (HR-TEM) results. These castings were checked for surface defects or sub-surface cracks using dye penetrant and ultrasound test. The amount of porosities present in all the castings was then determine precisely using Archimedes’ Principle of buoyancy. The experimental results thus found were validated with the simulation results obtained by AutoCAST simulation tool and improvements were incorporated by optimization of gating systems using modelling and simulation technique.