The role of TiN particles in enhancing the microstructure, tensile, and wear behavior of stir-cast AA7075-Zn alloy composites

Abstract

Titanium nitride-reinforced AA7075-Zn alloy composites were successfully synthesized via the stir-casting technique, and their microstructural, hardness, and wear behaviors were investigated. Microstructural analysis revealed a uniform dispersion of TiN particles within the AA7075-Zn matrix, contributing to grain refinement and enhanced interfacial bonding. The microhardness of the composites significantly increased from 62 HV0.1 for the AA7075 alloy to 152 HV0.1 for the 5 wt% TiN composite. Tensile strength also improved, with the 5 wt% TiN composites attaining 208 MPa, compared to 150 MPa for the base alloy. The wear behavior of the composites improved significantly, with the coefficient of friction decreasing as the TiN content increased. The composite reinforced with 10 wt% TiN exhibited superior wear resistance, demonstrating minimal plastic deformation. Fractographic analysis revealed a transition from ductile to brittle failure, characterized by dimples in the base alloy evolving into cleavage facets and particle pull-outs at higher TiN contents.