Numerical Validation of Thermal Expansivity of Al6061 Based Hybrid Nano Metal Matrix Composite Filled with Nanoparticles of Ni and Cr

Abstract

Aluminum 6061 (Al6061) is a commonly used aluminum alloy due to its better mechanical and thermal characteristics. This paper investigates the thermal properties of Al6061-based hybrid metal matrix composites, which are fabricated using a stir-casting technique. The composites are reinforced with varying weight percentages of nickel (Ni) and chromium (Cr) nanoparticles, while fixed weight percentages of graphene and magnesium nanoparticles are added to enhance self-lubrication and wettability. The coefficient of thermal expansion (CTE) of the composites is evaluated as a function of thermal strain and temperature difference over a temperature range of 50 to 300 °C. Results show that the CTE decreases with increasing reinforcement weight fraction up to 0.6 wt.% of Ni and 0.6 wt.% of Cr, but beyond this limit, further addition of reinforced particles results in an increase in CTE. At 300 °C, a hybrid nano metal matrix composite reinforced with 0.6 wt. % of Ni and 0.6 wt. % of Cr exhibits a minimum CTE of 19.7 x 10-6/°C, which is significantly lower than that of Al6061 (25.8 x 10-6/°C). To validate the experimental results, finite element analysis (FEA) is conducted to determine the thermal strain, thermal displacement, and thermal stress. The experimental findings are found to be in good agreement with the FEA outcomes. Overall, the results of this study suggest that the addition of Ni and Cr nanoparticles can effectively improve the thermal properties of Al6061-based hybrid metal matrix composites.