Effect of cathodic polarisation on stress corrosion cracking behaviour of a Ni(Fe, Al)-maraging steel in artificial seawater

• DOI: 10.1016/j.corsci.2020.109176
• Publication Date: 2020-12-03T16:46:34Z
• Authors: Tianliang Zhao; Shiqi Wang; Zhiyong Liu; Cuiwei Du; Xiaogang Li
• Keywords: Maraging steel; Artificial seawater; Embrittlement

Abstract The effect of cathodic polarisation on stress corrosion cracking (SCC) behaviour of peak-aged Ni(Fe, Al)-maraging steel in artificial seawater was investigated. The steel shows better compatibility of strength and hydrogen embrittlement (HE) resistance than reported 18Ni-type maraging steels when potential is above −850 mV. This advantage stems from the abundant and evenly dispersed Ni(Fe, Al) nanoprecipitates. SCC occurs above −850 mV in a transgranular/intergranular-mixed manner involving a mechanics-dominant-anodic-dissolution-promoted mechanism and below −850 mV in an intergranular manner along parent austenite grain boundaries involving HE. For interpreting the HE mechanism, a novel model is proposed based on hydrogen-weakening interatomic bonds.