Effects of Nano yttrium and Spark Plasma Sintering on the Mechanical Properties of AA2024 Matrix Composites

Abstract

The present research work investigates the effects of nano yttrium (Y) and SPS mechanism on various properties of AA2024-Y nanocomposites. Five nanocomposites are developed through SPS by reinforcing varying amounts of nano yttrium in the range of 0.1–0.5 wt% to the AA2024 powder matrix. An unreinforced AA2024 is also sintered by SPS as a benchmark to compare the mechanical properties. The microstructure characterization of the developed nanocomposites is carried out by optical microscope and field emission scanning electron microscope and the mechanical properties like microhardness and tensile strength is evaluated by computerized Vickers hardness testing machine and universal testing machine (UTM) respectively. The mechanical properties and the corresponding microstructures of composites are correlated. The experimental results showed that the mechanical properties gradually increased to a certain level and then decrease. There is a clear trend of initial increase and late decrease in the mechanical properties. An optimum amount of nano yttrium (0.3 wt%) addition is observed to be the maximum limit of reinforcement content to create favorable conditions during spark plasma sintering for the promotion of densification and Al2Cu precipitation in the α-Al matrix leading to an improvement in the mechanical properties of the nanocomposites. Among the developed composites, the highest hardness (130 HV), yield strength (YS) (386 MPa) and UTS (462 MPa) are obtained in the AA2024 composite sample reinforced with 0.3 wt% addition of nano yttrium. Densities close to theoretical density are achieved in all the composite samples.