Evaluating of the microstructure, texture, and mechanical properties of AA2024-Al3NiCu composites fabricated by the stir casting process

Abstract

The formation of nickel aluminides and their uniform distribution in the aluminum matrix due to their high thermal stability can improve the thermal instability of Al-Cu-Mg alloys. This research aims to study the effect of stir casting parameters, including stirring speed, stirring time, and temperature, on the microstructure, and mechanical properties of AA2024 aluminum alloy composite reinforced with Al-Ni intermetallic compounds. Also, the effect of time and temperature of artificial aging treatment on mechanical properties of AA2024-Al 3 NiCu composite investigated. To produce in-situ Al-Ni intermetallic compounds in aluminum, nickel additive was inserted to the molten aluminum during stir casting process. The results indicated that the amount of S-Al 2 CuMg precipitates decreased, and the number of Al 3 NiCu intermetallic compounds increased either by increasing the stirring temperature from 750° to 850°C or increasing the stirring time from 10 to 20 min. With increasing the stirring time from 10 to 20 min and increasing the stirring speed from 300 to 450 rpm, the preferred orientation of the aluminum matrix changed to the (220) plane with a P of 1.31 and 1.34, respectively. By adding 3 wt% Ni at stirring temperature of 750 °C, stirring time of 10 min, and stirring speed of 300 rpm, the maximum hardness 144.05 ± 9.27 HV, tensile strength 230.76 ± 8.45 MPa, and toughness 1.87 ± 0.14 MJ.m −3 were achieved.