Abstract
15 vol.-% SiC particle reinforced cast Mg – 9AlZn (AZ91C) composite was produced by a vacuum stir casting process, and the microstructure and mechanical properties of the composite investigated. The stirring process was carried out at a speed of 750 – 1500 rev min-1 with a stainless steel impeller for 25 min in a vacuum of 20 – 40 mbar. SiC particles in the composite exhibited a reasonably homogeneous distribution and were well wetted by magnesium. The Mg – Al9Zn/15SiCp composite showed significant improvement in yield strength and elastic modulus following T4 heat treatment. The ultimate tensile strength of the composite was low, but close to that of unreinforced magnesium alloy. Mg/SiC interfacial reactions and reaction mechanisms are discussed. No evident interfacial products were found at a low process temperature of 700°C. However, significant chemical reactions at the Mg/SiC interface occurred when the composite melt was maintained at 750°C, and complex reaction products were formed. The fluidity of the composite melt deteriorated seriously after the interfacial reactions occurred.
Keywords
Get full access to this article
View all access options for this article.
