Study On Corrosion Damage Of The Typical Aluminum Alloy Of Air Force Plane And The Test Of Accelerated Corrosion

With the increasing effects of corrosive environment on the aircraft structures, calendar life has become a severe trouble of the air force at present and in the future. In this paper, the engineer background, the core technology, the existing status quo and the problem of the military aircraft calendar life at home and abroad were expounded. Several key problems were studied emphatically, such as corrosion feature, corrosion mechanism, failure mode, probabilistic distribution and development of corrosion damage, the accelerated corrosion test environment spectrum and corrosion equivalent relationship. The main progresses of this paper are as following.1. In accordance with the typical service environment of the aircrafts of our air force, the typical corrosion feature and corrosion mechanism in the structures of aluminum alloy base and its anticorrosive coatings were studied, corrosion development of the typical aluminum alloy structures were analyzed. Then the foundation was offered for establishment of the accelerated corrosion test environment spectrum and experimenting method.2. In accordance with the status quo of the aircraft corrosion in our air force, one type of key structures due to corrosion in a certain type aircraft were chosen to investigate accelerated corrosion test environment spectrum and experimenting method. On the basis of experimenting results, above accelerated corrosion test environment spectrum and experimenting method can reproduce corrosion failure of above key structures during their service period.3. Based on above accelerated corrosion test, establishment of corrosion equivalent relationship is determined by contrasting the degree of corrosion.4. The distribution and development of corrosion damage of LY12CZ were studied by the accelerated corrosion experiments in accordance with EXCO immersion test method. Based on statistic of experimental data, the probability density function of maximum corrosion depth accord with Gumbel, Weibull, double parameter Weibull and logarithmic Weibull distribution were formed and their parameters were determined. Then the maximum corrosion depth of typicalstructures of a certain type aircraft was estimated.5. By the investigation of corrosion behavior of LY12CZ immersed EXCO solution, the relationship between the maximum corrosion depth and corrosion degree. Then the corrosion degree in typical aluminum alloy structures of aircraft can be quantified.