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Abstract Pitting corrosion is a common form of damage in aviation aluminum alloy materials in service. Pitting damage can lead to the deterioration of material properties, impair the bearing capacity of the structure, and seriously affect the flight safety and service life of the aircraft. Used for the bearing members, the aviation aluminum alloys are subjected to not only environmental corrosion, but also stress. Therefore, it is of great theoretical and practical significance to study the pitting corrosion damage of aluminum alloy under stress. According to the basic principle of pitting, this paper introduces the porosity of the damage variable which characterizes the hole damage of the material. Considering the mechanical chemistry effect, the calculation model of the elastic modulus of pitting damage material under stress is established, which provides a necessary foundation for the prediction of the deterioration of structural bearing capacity. Accelerated corrosion test and uniaxial tensile test were carried out using the 2219 aluminum alloy. The SZX12 research-grade microscope and laser range finder were used to study the change of pitting depth with time and load. The pitting porosity and stress tested at different times were in exponential relationship, verifying the effect of mechanical chemistry on the porosity of pitting damage. It is proved that a corrosion pit in the aluminum alloy can be simulated as a semi-ellipsoid; that is, the pit can be regarded as an ellipsoidal hole damage in the material caused by the corrosive action. The macroscopic morphology of the damaged specimens after corrosion was observed and analyzed, and the influences of corrosion time and applied load on pitting damage were further verified. The comparison between the calculated results and the experimental data shows the correctness of the method and the feasibility to apply the damage mechanics to the description of corrosion damage. This study also provides a new idea for the quantitative description of corrosion damage under stress.
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Received: 17 August 2018
Published: 11 April 2019
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2019, Vol. 40 
