Study On Corrosion Behaviors Of The LY12CZ Aluminum Alloy Plane Component

With increasing of the plane's calendar time, it's structure corrosion has become grave and restricted aviation safety , the serious problems defending and mending regularly. This paper has introduced that aviation aluminium alloy structure's corrosion and the project background under corrosive environment ,and summed up the general situation and problems that the same kind studies at home and abroad, and carried out more thorough research about that the LY12CZ aluminium alloy corrosion key technologies such as developing course and corroding an impact of mechanism and corrosion behavior to fatigue life. Five aspects has got bigger progressing and technology breakthrough as follows:1.The 20% EXCO solution is put into effect with soaking the corrosion experiment , making use of the method that the SZX12 microscope and MCS-7200 image analysis system shoot voluntarily at the regular intervals , the entire proceeding had studied LY12CZ aluminium alloy corrosion happens , develops under exposed state. By shooting acquisition's the data we get the continuous automation the regular intervals corroding process, and analysed the LY12CZ aluminium alloy three corrosion stages in EXCO solution from pitting to intergranular corrosion and denudation.2. The aluminium alloy immersed corrosion experiment carries out for 2 h , 4 h , 6 h and 12 h and then having carried out a fatigue test in 20% EXCO solution., determining corresponding fatigue life .By analysising the fatigue life , we get the fatigue life (N) relation with strain (S) and the LY12CZ aluminium alloy soaking time (t), having built the S-N curve:S^4.2007 N=10^6.2861 t^0.017673.It has been measured the loss of specimen after corrosive fatigue experiment, and got the corresponding corrosion time corrosion pit geometry parameter (corrode pit count, depth etc.) , and analysed the impact of average corrosion pit depth d on fatigue life , and built the relation corrosive pit average depth and fatigue life:S^4.2007 N=10^5.9381 (10^{1.3661 Lgd})^0.017674.Coated with LY12CZ, Researching the aluminium alloy structure corrosion process from the coating failure to substrate corrosion under protection coating circumstances, and compared with the samples uncoated.and analysis the differences of aluminium alloy corrosive behavior between coated and uncoated5. Based on the experimental data under the corrosive environment and the corrosive damage parameter. The engineering calculate method of LY12CZ aluminium structure fatigue life has been built under corrosive environment by FEM and AFGROW software.The calculate result has been absolutely according with the fatigue experiment life.