Fabrication and analysis of Zn-SiC metal matrix composites via advanced metallurgical processes

Abstract

This study focused on the processing and properties of zinc-silicon carbide (Zn-SiC) metal matrix composites utilizing upgraded metallurgical processing methods. Zn-SiC composites were made following three liquid metallurgy routes; stir casting, squeeze casting along with powder metallurgy methods with different percentages of SiC particles (5, 10, 15, and 20 wt%). The composite materials were characterized based on microstructural features, mechanical properties and thermal properties. Most importantly, it was shown that SiC particles were incorporated in the zinc matrix which increased the metals mechanical properties were intact with the composites. A maximum limit of 15 wt% SiC appeared to be the optimal percentage based on its tensile strength which increase 85%, along with hardness which increase 120% based on pure zinc. Microstructural characterization revealed the fully homogeneous zoning of SiC particulates in the zinc with very little interfacial reactions. Limited testing of Zn-SiC composites produced by the squeeze cast method, resulted in higher properties when compared too stir cast and powder metallurgy method. In addition thermal characteristics demonstrated the composites exhibited improved thermal stability and a reduced thermal expansion coefficient with increasing SiC particulates content. To conclude, the Zn-SiC composites represent a potential lightweight material system with good mechanical properties and enhanced thermal management for electronics, automotive and aerospace application where this could be critical.