Analysis of tensile strength, hardness, and fracture surface of aluminum silicone (Al-Si) with various copper (Cu) percentages using stir casting method

Aluminum-silicon (Al-Si) alloy is one of the most widely used non-ferrous metals in automotive components due to several advantages compared to other aluminum alloys. The mechanical properties of Al-Si can be improved with optimal parameters and integration processes such as combining aluminum silicon (Al-Si) with 1.5%; 2.5%, and 3.5 wt% copper (Cu) using a casting process. The Al-Si in this research was piston waste that was not to be reused. The study was conducted to determine the tensile strength, hardness, and fracture morphology of the Al-Si alloy without the addition of Cu as the control specimen and with the addition of 1.5; 2.5; and 3.5 wt% Cu using the stir casting method. The tensile strength and hardness tests increased following the additional Cu composition. The results showed that the raw material alloy had 12.395 Kg.F/mm2 tensile strength and 121.9 HV hardness. The largest improvement was found at the sample with additional 3.5 wt% which had the highest value of 20.13 Kg.F/mm2 tensile strength and 205.5 HV hardness, or an increase of 38.43% in tensile strength and 40% in hardness compared to raw material. As for the Strain, the increasing number of additional Cu, the strain value decreased due to the presence of the Al2Cu phase, which had hard and brittle characteristics.