The inhibitive action of 3-Ethyl-4-amino-5-mercapto-1, 2, 4-triazole on the corrosion behavior of 6061 Al -15 vol. pct. SiC(p) composite and its base alloy was studied at different temperatures in sulphuric acid medium containing varying concentrations of it, using Tafel extrapolation technique and AC impedance spectroscopy (EIS). Results showed that EAMT was an effective inhibitor, showing inhibition efficiency of 85% in 0.5 M sulfuric acid. The adsorption of EAMT on both the composite and base alloy was found to be through chemisorption obeying Langmuir adsorption isotherm. The thermodynamic parameters such as free energy, enthalpy and entropy of adsorption, and activation parameters were calculated.