Synthesis and Characterization of Novel Aluminum Composites: A Compo-Casting Approach with ZrO2 , Al2O3 , and SiC

Abstract

The present study evaluates the microstructural features, mechanical properties, and wear characteristics of the newly developed hybrid composite of A356/ZrO2/Al2O3/SiC produced by compo-casting at 605±5 °C, 600 rpm for 15 minutes with less than 30% solid fraction in which Bi and Sn were added separately to the matrix before introducing reinforcements. FESEM micrographs and corresponding EDS illustrated the successful incorporation of particles in the matrix. Fine particles of ZrO2 were observed close to the coarse Al2O3, and SiC particles, along with Bi and Sn elements, were detected at the eutectic evolution region. The A356+Bi/Al2O3+ZrO2+SiC hybrid composite exhibited the lowest specific wear rate (1.642 ×10-7cm3/Nm) and friction coefficient (0.31) under applied loads of 5, 10, and 20 N, in line with the highest hardness (73.4 HBN). Analysis of the worn surfaces revealed that the wear mechanism is mostly adhesive in all synthesized composites, which changed to the combination of adhesive and abrasive mode in the case containing Bi and SiC. Inserting Bi not only leads to the refinement of eutectic Si but also enhances the adhesion between the matrix/particles and improves lubricity. This, in turn, reduces the wear rate and coefficient of friction, ultimately improving the performance of the hybrid composite.