Influence of corrosion and tribocorrosion on damageability and cyclic durability of materials

Abstract

The paper deals with corrosion and tribocorrosion testing of the AA7075 + NiCrCoHfNbAlWCTiBZrC composite. The chemical analysis of condensate on fuselage of a Boeing, shows its ionic and salt composition, which allows to reproduce artificial condensate. Corrosion damage of aircraft structures caused by artificial condensate is similar to that caused by natural condensate. Cyclic fatigue testing of aircraft materials is conducted in different corrosive media. The statistical analysis is conducted for the corrosion rate affecting the low-cycle fatigue durability. Aviation materials are subjected to corrosion destruction caused by artificial condensate and corrosive media (3% NaCl, NaCl + H₂O₂, K₂Cr₂O₇ + HCl solutions). After the statistical analysis of the results, empirical equations are suggested for the cyclic fatigue durability and corrosion rate. An empirical equation is suggested for the crack growth depending on the stress intensity factor. The corrosion destruction of aviation materials demonstrates that each jump in the crack propagation captures a significant part of the grain boundary not involved in the interaction with the corrosive medium.