Characterization of the corrosion influence on the fatigue behaviour of intrinsic CFRP-steel hybrids

Abstract

Hybrid structures provide the opportunity to design load-adapted components by complete or local CFRP strengthening and offer a high potential for lightweight construction. Such components are exposed to mechanical and environmental loads under service conditions, e.g. in automotive applications. In the present study the influence of a pre-corrosive deterioration and in-situ salt spray load on the fatigue behavior of two intrinsically produced hybrid structures with different steel constituents was investigated using in-situ strain and temperature measurements in order to obtain a precise description and prospective prediction. The corrosion behavior was characterized in potentiodynamic polarization measurements and afterwards correlated with the fatigue results, yielding a process-structure-property relationship of the corrosion influence on the fatigue performance. Both hybrid structures exhibited galvanic corrosion, yet one material combination showed significantly higher corrosion rates leading to a worse fatigue behavior observed in single step tests with pre-corroded specimens and in corrosion fatigue tests in salt spray environment. Light microscopy investigations were performed to describe macroscopic mechanical-chemical properties on microstructure basis.