Effect of Ce addition on microstructure, mechanical properties and corrosion behavior of Al-Cu-Mn-Mg-Fe alloy

Abstract

Abstract The effects of rare earth Ce on the microstructure, mechanical properties and corrosion behavior of Al-Cu-Mn-Mg-Fe alloys were investigated by means of microstructure analysis, tensile test and electrochemical corrosion test. The research shows that the Al-Cu-Mn-Mg-Fe alloy after low temperature heat treatment mainly contains the S (Al2CuMg) phase, the T (Al20Cu2Mn3) phase, the Al6 (Mn, Fe) phase and the Al7Cu2Fe phase, and the rare earth Ce makes the alloy form the new rare earth phase Al8Cu4Ce. The appearance of this phase has a significant refinement effect on the Al6 (Mn, Fe) phase. Compared with Ce-free, the yield strength and tensile strength of Al-Cu-Mn-Mg-Fe alloy with 0.254 ωt% Ce increased by 7% and 15%, respectively, and the elongation increased from 3.1% to 4.8%. It also has better corrosion resistance, which is represented by the decrease of corrosion current density and positive shift of corrosion potential in Tafel measurement in solutions of different concentrations, and the increase of corrosion impedance in electrochemical impedance spectroscopy test, especially the corrosion current density was reduced by 6.06 μA cm−2 in 3.5% NaCl solution.