Aluminum alloys are widely used in various industrial applications due to their low weight and favorable mechanical properties. Consequently, extensive research has been conducted to further enhance these properties. In this study, the Al-11%Si alloy was modified by adding varying amounts of antimony (Sb) metal powder: (0.05, 0.1, 0.2, 0.3, and 0.4 wt %), to enhance the mechanical characteristics including the tribological and tensile behavior. The mechanical properties of the modified alloys were thoroughly evaluated. The optimal mechanical performance was achieved with the addition of 0.3% and 0.4% Sb. The casting process involved melting a measured amount of the Al-11%Si alloy at 720 °C in an electric furnace. Antimony powder was then introduced into the melt, which was stirred at 250 r.p.m. for 5 minutes at three stages to form a vortex and ensure uniform dispersion of the modifier. The melt temperature was carefully monitored and controlled using a thermocouple before being poured into a carbon steel mold. Several tests were conducted on the modified alloys, including microstructural analysis, hardness, tensile strength, surface roughness, and wear resistance assessments. The addition of the antimony element (Sb) was found to significantly refine the microstructure and transform the morphology of silicon particles from a flake-like or lamellar form to a more fibrous structure. Furthermore, Sb additions of 0.05%, 0.1%, and 0.2% wt improved micro hardness (Hv), yield strength (YS), and ultimate tensile strength (UTS), while simultaneously reducing surface roughness (Ra) and wear-rate (Wr).
Viscoelasticity, as its name implies, is a generalization of elasticity and viscosity. Many industrial applications use viscoelastic matrix with reinforcement fiber to obtained better properties. Tensile testing of matrix and one types of fabric polyamide composites was performed at various loading rates ranging from (8.16* 10-5 to 11.66 * 10-5 m/sec) using a servohydraulic testing apparatus. The kind of reinforcement, random glass fiber (RGF), and the kind of matrix, epoxy (E) are used shown that the linear strain (،ـ 0.5) for the three parameter model gives a good agreement with experimental results. The results showed that both tensile strength and failure strain of these matrices and composites tend to decrease with increase of strain rate. The experimental results were comparison with numerical results by using ANSYS 5.4 program for simple study case has shown some agreement. Fracture regions of the tested specimens were also observed to study micro mechanisms of tensile failure.