Correlation between cavitation erosion resistance and cyclic mechanical properties of different metallic materials

6th International Conference on Fracture Fatigue and Wear

Kaufhold, Corinna^1 ; Pöhl, Fabian^1 ; Theisen, Werner^1

Department of Materials Technology, Ruhr University Bochum, Bochum

44801, Germany^1

关键词: Austenitic stainless;    Carbon and nitrogen;    Cavitation erosion resistance;    Cavitation impacts;    Contact stiffness;    Incubation periods;    Indentation hardness;    Nanoindentation experiments;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/843/1/012037/pdf
DOI  :  10.1088/1742-6596/843/1/012037

来源: IOP

【 摘 要 】

Machine components in contact with flowing fluids are especially prone to cavitation erosion, where plastic deformation and material loss occur due to the repeated implosion of cavitation bubbles in the vicinity of a solid surface. Identifying a correlation between experimentally derivable material properties and resistance against cavitation erosion could help improve the lifetime of cavitation-affected components. Cavitation erosion is a predominantly fatigue-driven phenomenon. In this investigation, we conducted nanoindentation experiments to examine cyclic micromechanical material properties in response to an increasing number of cycles. The experiments were performed on pure iron and different steel grades, i.e., austenitic stainless CrMnCN steels, interstitially alloyed with carbon and nitrogen. We confirmed the view, also proposed in literature, that indentation hardness is inappropriate for ordering the investigated materials by incubation period or maximum erosion rate. We found that the percentage increase of nanoindentation contact stiffness, after an increasing number of cycles, is a promising indicator in terms of the overall ranking of cavitation erosion resistance among the considered materials. Although a single cavitation impact is associated with a significantly higher strain rate than nanoindentation experiments, it is shown that the plastically deformed area around each indent exhibits indications of deformation, such as the formation of slip lines that are also observable after cavitation-induced impacts.