Microstructure and mechanical properties of Zn25Al3Cu based composites with large Al<inf>2</inf>O<inf>3</inf> particles at room and elevated temperatures

Abstract

Microstructures and compressive properties of Zn25Al3Cu alloy and Zn25Al3Cu/Al2O3 particulate composites with large reinforcing particles (250 μm) were examined. The composites were obtained by the compocasting technique through infiltration of 3, 8 and 16 wt.% Al 2O3 particles into the semi-solid metal matrix. The influence of temperature in the range from 70 to 170°C on compressive yield strength of the matrix alloy (as-cast and thixocast Zn25Al3Cu alloy) and the composites was investigated. Above 70°C compressive yield strength of all materials decreases, but the rate of decrease is different for the matrix alloy (as-cast and thixocast) and composites. It was found that the abrupt decrease in compressive yield strength of the matrix alloy occurred at temperatures higher than 70°C, whereas composites retained relatively high values of compressive yield strength till the end of the testing temperature range regardless of the amount of reinforcing particles. © Carl Hanser Verlag GmbH & Co. KG ISSN 1862-5282.