Microstructural, Mechanical and Wear behaviour of in-situ Al-TiB2 composites

Abstract

ABSTRACT In this study, mechanical and wear properties of in-situ stir cast Al-TiB2 composites were investigated. The composites were prepared by a metal salt reaction with different (3.0, 5.0 and 7.0 wt %) TiB2 contents. The microstructure of the composites were examined through an optical and scanning electron microscopy (SEM/EDS). The microstructures clearly revealed the uniform distribution of TiB2 particles in the Al matrix. The hardness of the in-situ Al-TiB2 based composites increased by 42%, 55%, and 58% compared to the matrix with the addition of 3, 5, and 7 wt% TiB2 reinforcements, respectively. The tensile strength of the 3, 5, and 7 wt% TiB2 stir-cast composites increased by 25%, 33%, and 45%, respectively, compared to the matrix, whereas the ductility decreased by 4.9%, 24.3%, and 41.3%, respectively. A pin-on-disk tester was used to perform a dry sliding wear test at different loads and sliding speeds. In comparison to the Al matrix, the composite materials showed improved wear resistance. Furthermore, in the entire applied loads and sliding velocities, the wear rate decreased with the increase in TiB2 content. The composites displayed lower wear rates due to their high hardness and strong interfacial bonding between the in-situ reinforcement and the matrix alloy.