Effect of Al2O3 nanoparticles and strontium addition on structural, mechanical and tribological properties of Zn25Al3Si alloy

Abstract

Nanocomposites were synthesized via compocasting using Zn25Al3Si and Zn25Al3Si0.03Sr alloys as the matrices and nanoparticles of Al2O3 (1 wt%) as the reinforcement. Structure of the nanocomposites was examined, and their basic mechanical and tribological properties were tested. Distribution of primary silicon particles in the structure of nanocomposites has been improved compared to their distribution in the Zn25Al3Si matrix alloy due to the presence of Al2O3 nanoparticles and strontium. The primary silicon particles in the structure of the nanocomposites were found to be more fine-grained compared to the same particles in the structure of the as-cast Zn25Al3Si alloy. Tested mechanical properties of the nanocomposite with Zn25Al3Si alloy matrix are improved, compared to the matrix alloy. The nanocomposite with Zn25Al3Si0.03Sr alloy matrix is characterized with slightly higher value of compressive yield strength and a slightly lower hardness value compared to the as-cast Zn25Al3Si alloy. Both nanocomposites showed lower wear rate and higher coefficient of friction, compared to the matrix alloy, in sliding under the boundary lubricating regime. However, the nanocomposite with Zn25Al3Si alloy matrix showed better tribological properties than the nanocomposite with Zn25Al3Si0.03Sr alloy matrix.