Corrosion Product Film-Induced Stress Facilitates Stress Corrosion Cracking.

Wenwen Wang,Yanjing Su,Yongjun Guan,Xuechong Ren,Zhiliang Zhang

doi:10.1038/srep10579

Abstract

Finite element analyses were conducted to clarify the role of corrosion product films (CPFs) in stress corrosion cracking (SCC). Flat and U-shaped edge-notched specimens were investigated in terms of the CPF-induced stress in the metallic substrate and the stress in the CPF. For a U-shaped edge-notched specimen, the stress field in front of the notch tip is affected by the Young’s modulus of the CPF and the CPF thickness and notch geometry. The CPF-induced tensile stress in the metallic substrate is superimposed on the applied load to increase the crack tip strain and facilitate localized plasticity deformation. In addition, the stress in the CPF surface contributes to the rupture of the CPFs. The results provide physical insights into the role of CPFs in SCC.

Highlights

Stress corrosion cracking (SCC) is an event that is caused by the combined effect of a stress and corrosive environment
If the cations move outward at a faster rate than the anions move inward, a corrosion product films (CPFs) grows at the film/solution interface with numerous cation vacancies remaining on the metal side, which will produce a tensile stress at the inner interface and a compressive stress in the CPF17
Our previous experiments and finite element method (FEM) analyses revealed that compressive stress and tensile stress can be generated in the CPF and the copper substrate, respectively, due to the volume difference between the ionized metal and the oxide

Summary

Introduction

Stress corrosion cracking (SCC) is an event that is caused by the combined effect of a stress and corrosive environment. The SCC of copper in an ammoniacal solution was considered to be a finite element model, and the distributions of the CPF-induced stress in the flat and U-shaped edge-notched specimens were simulated. A tensile CPF-induced stress is observed at the interface on the substrate side, which increases with an increase in CPF thickness.

Results

Conclusion