Tensile properties of cold chamber die cast ceramic particulate-reinforced ZA-8 composites

Zinc-Aluminum alloys have competed successfully against several aluminum alloys, bronzes and cast irons because of their low cost, good castability and attractive room temperature tensile properties. However, the extent of applications has been reduced by their limited high temperature properties. Reinforcement of Zinc-Aluminum alloys by ceramic particulate offers the opportunity to significantly improve properties such as specific modulus, high temperature strength and creep resistance. Nominally 15 and 30 vol% ceramic particulate (Cr23C6 and TiB2) were added to ZA-8 alloy using a stir casting facility developed at MTL for ILZRO. The resulting composite ingots were remelted and cold chamber die cast. This paper discusses the die casting characteristics of the new ZA-8 composites, their microstructure, hardness and tensile properties at room and high temperature.