Corrosion behavior of novel Cu-Ni-Al-Si alloy with super-high strength in 3.5% NaCl solution
(1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University, Changsha 410082, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China)
2. Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University, Changsha 410082, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract: A novel Cu-6.5Ni-1Al-1Si-0.15Mg-0.15Ce alloy with super-high strength was designed and its corrosion behavior in 3.5% NaCl solution at 25 °C was investigated by the means of SEM observation, TEM observation and XPS analysis. The alloy after solution treatment, 80% cold rolling and aging at 450 °C for 1 h had the best comprehensive properties with hardness of HV 314, electrical conductivity of 19.4% IACS, tensile strength of 1017 MPa, and average annual corrosion rate of 0.028 mm/a. The oxides and chloride products formed at first, followed by the formation of dyroxides products. The alloy showed super-high strength, good electrical conductivity and corrosion resistant because Ni2Si hindered the precipitation of large NiAl at the grain boundary and the denickelefication of the alloy.
Key words: Cu-Ni-Al-Si alloy; Ni2Si precipitate; corrosion behavior; average annual corrosion rate; corrosion product