Effects of Al addition on corrosion behavior and mechanical property of high-strength and high-elasticity Cu-20Ni-20Mn-0.3Nb-0.3Cr-0.3Zr alloy

Abstract High-strength and high-elastic copper alloy not only has super mechanical properties, but also has good corrosion resistance. Therefore, it is widely used in marine engineering. In this paper, three kinds of CuNiMnNbCrZr alloy with different Al contents are designed. And their mechanical properties and corrosion behavior in 3.5 wt.% NaCl solution were studied. The Cu-20Ni-20Mn-0.3Nb-0.3Cr-0.3Zr alloy has good mechanical properties (Tensile strength: 1445MPa, Yield strength: 1223MPa, Elongation: 6.8%) and nice corrosion resistance (Corrosion rate: 0.0087mm/a). By comparing the polarization resistance, self-corrosion potential, equivalent resistance and XPS analysis of three alloys, a further enhanced corrosion resistance is found in the alloy with Al element added. The results revealed that a dense Al2O3 film was formed during the corrosion process, which prevented the substrate from being corroded. These newly developed high-strength and high-elasticity copper alloys have great potential for marine environment applications.