Effect of TiB2 on mechanical and corrosion properties of Al 7075/TiB2/Gr composite prepared by stir casting

Abstract

The current study examined the microstructural, mechanical, and corrosion properties of a metal matrix composite based on an aluminium alloy (AA7075). Three types of stir-cast metal matrix composites were created by reinforcing varying amounts of titanium diboride (2, 4, and 6 wt%) in the base alloy aluminium AA7075 while keeping the graphite content constant at 5 wt%. The optical microstructural features show that the alloying additions of graphite and titanium diborides have been homogeneously mixed in the matrix phase with no agglomeration. The tendency of particle segregation along the inter-dendritic region increases as titanium diboride content increases. The hardness and tensile properties of composite materials increase as the weight percentage of titanium diboride increases. Although the increase in hardness is small,the increase in tensile properties is significant and significantly greater than the base aluminium alloy AA7075. The corrosion rate of three metal matrix composite variants was determined using the weight loss method in three different corrosive solutions: aqueous (water), acidic (HCl - Concentration 0.3 N), and basic (NaOH - Concentration 0.3 N). The overall corrosion rate of all composites is significantly lower in aqueous solutions compared to acidic and basic solutions. The composite containing 4% titanium diboride has the highest corrosion rate in both acidic and basic solutions.