Effect of nanoprecipitate on the stress corrosion cracking behavior of Cu-rich nanoprecipitate-strengthened high-strength steels

This work focuses on the role of Cu-rich nanoprecipitates in stress corrosion cracking (SCC), elucidated by comparing the SCC mechanisms in solution-treated and aged 1000 MPa-grade high-strength steels. Research findings indicate that the precipitation of 9R-structured Cu-rich nanoprecipitates enhances the resistance to SCC by suppressing both hydrogen embrittlement (HE) and anodic dissolution (AD). X-ray photoelectron spectroscopy and electrochemical tests reveal that the corrosion products of the aged steel contain a higher content of thermodynamically stable phases (e. g.: CuFeO2, Fe2O3, and Al2O3), which contribute to enhanced corrosion resistance and reduced AD. Fast and slow scan rate potentiodynamic polarization tests reveal that after aging treatment, the equivalent hydrogen charging current density is significantly reduced from 14.4 µA/cm2 to 4.8 µA/cm2, indicating a significant decrease of HE susceptibility.