Aluminum is one of the most important materials with various usages. It has important features such as lightness, corrosion resistance, the compatibility with heat treatment, formability and affordable price. Conversely, Al-Cu alloys are extensively employed in the aerospace industry because of their exceptional combination of high specific strength and excellent machining characteristics. In this alloy, copper increases the strength of the material as it forms intermetallic compounds with alloying elements. Moreover, precipitation hardening is possible by dissolving copper in aluminum in the solid phase. This study examines the microstructure and mechanical properties of composites with matrix of Al-Cu alloys. To accomplish this, the initial step involved melting the Al-Cu alloy at a temperature of 800 °C, followed by the addition of 0.3% and 0.5% steel powder by weight into the molten mixture. The Al-Cu melt mixed at 300 rpm for 10 minutes, was controlled with aluflux and degassing tablets and the resulting mixture was cast into a steel mold. The Al-Cu alloys of the heat treatment were fulfilled at 500 degrees for 2 h and then they were cooled in water. The aging process of T6 was carried out by keeping it in an annealing furnace at 150 and 200 degrees for 1 and 3 h. Following the manufacturing procedures, the samples were polished and etched to facilitate microstructural studies. The obtained Vickers hardness values were analyzed with the Taguchi method and the results were evaluated. The maximum hardness value recorded in this study was 263.86 HV. The Al-Cu casting alloy exhibited a relatively higher density, indicating lower porosity, when a synergistic combination of 0.3% steel powder additive and a 1-hour aging time was applied.