scholarly journals Research on Corrosion Damage Evolution of Aluminum Alloy for Aviation

2020 ◽  
Vol 10 (20) ◽  
pp. 7184
Author(s):  
Zhigang Gao ◽  
Yuting He ◽  
Sheng Zhang ◽  
Tianyu Zhang ◽  
Fei Yang
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Rate ◽  
Early Stage ◽  
Three Dimensional ◽  
Gumbel Distribution ◽  
Corrosion Damage ◽  
Environmental Data ◽  
Evolution Law ◽  
Immersion Corrosion ◽  
Corrosion Pits

Based on the real annual average value of atmospheric environmental data in the Wanning area of Hainan Province in China by selecting 7075 ultra-high-strength aluminum alloy specimens for aviation, a new corrosion solution was designed and the traditional alternate immersion corrosion method of using the alternate immersion corrosion test box was improved to simulate the environment of the internal structure of the aircraft. On this basis, two kinds of corrosion damage parameters, the depth of corrosion pits and corrosion rate, were quickly and accurately obtained by the three-dimensional profile of the specimen and binarization images’ method. The optimal linear regression equation combination of pitting depth and corrosion rate was established, and the dynamic evolution equation of the depth of corrosion pits and corrosion rate was obtained. The results showed that: The depth of corrosion pits in the early stage of corrosion (8 h and 24 h) obeyed the Gumbel distribution and Weibull distribution, respectively, and the later stage (48 h, 72 h, 96 h, and 120 h) conformed to the normal distribution; the depth of corrosion pits’ evolution law was in the form of double straight lines and the corrosion rate evolution law was in the power function form (y = a × xb); and the depth of corrosion pits changed rapidly in the early stage and gradually slowed down in the later stage, while the corrosion rate was just the opposite.

scholarly journals Application of Kelvin Probe Force Microscopy (KFM) to Evidence Localized Corrosion of Over-Aged Aeronautical 2024 Aluminum Alloy

2013 ◽  
Vol 550 ◽  
pp. 127-134
Author(s):  
Nicoleta Radutoiu ◽  
Joël Alexis ◽  
Loïc Lacroix ◽  
Marioara Abrudeanu ◽  
Jacques Alain Petit
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Corrosion Damage ◽  
Localized Corrosion ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Intermetallic Particles ◽  
2024 Alloy ◽  
The Matrix

The 2xxx serie aluminum alloys are characterized by good mechanical performances and low density, however they are susceptible to different forms of localized corrosion: pitting corrosion, intergranular corrosion and stress corrosion cracking. The 2024-T351 aluminum alloy is used in the aircraft industry for numerous applications such as fuselage and door skin. Corrosion damage of the material is also very detrimental for the structural integrity of the aircraft. The presence of coarse intermetallic particles, with a heterogeneous size distribution was found to be responsible for the 2024 susceptibility to localized corrosion. These particles are generally the cause of initiation sites. Presence of micro-defects in the oxide film upon coarse intermetallic particles and the galvanic coupling with the matrix contribute to the development of pitting corrosion. The over-ageing treatment (T7) is supposed to stabilize the microstructure and the mechanical properties to improve the corrosion resistance. The 2024 alloy microstructure after the T7 heat treatment remains very complex. The 2024 alloy corrosion behavior was studied in the over-ageing state for three different temperatures (150, 175 and 190 °C). During the corrosion tests in chloride-containing environment, the behavior of coarse intermetallic particles was found to be different. Thus, the 2024 samples suffer a gradual attack upon S-Al2CuMg particles and finally Al (Cu,Mn,Fe,Si) particles. The corrosion damage was studied by Atomic Force Microscopy (AFM) and Kelvin probe Force Microscopy (KFM). This technique allows simultaneous topographical and electric potential mapping to be obtained. This latest potential was shown to be correlated to the corrosion potential of the 2024 alloy. This study focuses on the variation of the KFM potential of the coarse intermetallic particles and the matrix for the over-ageing conditions (T7). Observations using optical microscope and AFM were also performed to obtain the corrosion rate for each condition. The corrosion rate was correlated to the chemical composition variation of the particles obtained by scanning electron microscope observations and EDS analyses.

Fatigue Crack Growth of LC9 Aluminum Alloy under Flying Loading with Corrosion Damage

2014 ◽  
Vol 488-489 ◽  
pp. 66-69
Author(s):  
Xu Dong Li ◽  
Zeng Jie Cai ◽  
Zhi Tao Mu
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Corrosion Damage ◽  
Growth Behavior ◽  
Transport Aircraft ◽  
Suitable Parameter ◽  
Corrosion Pits

This paper investigates the growth behavior of fatigue cracks initiated at corrosion pits in laboratory coupons of LC9 aluminum alloy subjected to a transport aircraft loading spectrum. Corrosion pits were introduced by exposing the coupons to EXCO solution for a variety of periods to produce corrosion damage varying from mild to severe. In general, the presence of corrosion damage reduced the fatigue lives of components to a severe extent. It was found that the depth of the corrosion pit was a suitable parameter for characterizing the corrosion damage and for predicting the fatigue life of the coupons using commercial fatigue crack growth software

The Corrosion Morphology and Crack Growth Analysis of Aluminum Alloy

2011 ◽  
Vol 80-81 ◽  
pp. 464-468
Author(s):  
Zhi Tao Mu ◽  
Hui Liu ◽  
Zuo Tao Zhu ◽  
Ding Hai Chen
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Crack Growth ◽  
Growth Analysis ◽  
Three Dimensional ◽  
Critical Crack ◽  
Corrosion Morphology ◽  
Critical Crack Length ◽  
Corrosion Depth ◽  
Corrosion Pits

The relation between corrosion depth and width with corrosion time is according with the power function. The corrosion pits can be seen as ellipse balls through the examination of QUESTAR three-dimensional optics microscope. Corrosion can decrease the fatigue life of materials and is the main reason of fatigue crack form and grow; through AFGROW analyze we can see that the AFGROW software can simulate crack growth life well and the error is low, the crack growth life and critical crack length are conservative than experiment values.

Probabilistic Study on Corrosion Damage Distribution and Fatigue Lives of LY12CZ Aluminum Alloy Structure

2011 ◽  
Vol 66-68 ◽  
pp. 594-597
Author(s):  
Da Zhao Yu ◽  
Yue Liang Chen ◽  
Zhang Yong ◽  
Qing He Fan
Keyword(s):  
Aluminum Alloy ◽  
Probabilistic Neural Network ◽  
Gumbel Distribution ◽  
Corrosion Damage ◽  
Crack Size ◽  
Distribution Functions ◽  
Distribution Law ◽  
Corrosion Depth ◽  
Prediction Program ◽  
Damage Depth

A probabilistic neural network was developed to classify corrosion damage depth ranges based on the aluminum alloy failure mode. The results obtained indicate that corrosion damage depth for aluminum alloy can be classified into three groups. Statistical study on classified corrosion damage was carried out. The results show that pitting corrosion depth for aluminum alloy is in conforms to Gumbel distribution. The normal distribution fits well with intergranular corrosion depth and the exfoliation corrosion depth is consistent with Weibull distribution law. It may be necessary to use several distribution functions rather than a single distribution to represent corrosion damage characteristics due to the large distribution of corrosion depth in aircraft materials. According to corrosion damage depth distribution, corrosion depth was simulated by Monte Carlo method and used as the starting crack size. Fatigue lives were estimated by using a life prediction program AFGROW and the results are in good agreement with the experimental data. A probabilistic analysis shows that the distribution of fatigue lives is strongly correlated to the distribution of corrosion damage depth and should be classified into several groups to study.

The corrosion behavior of marine aluminum alloy MIG welded joints in a simulated tropical marine atmosphere

2021 ◽  
Vol 63 (2) ◽  
pp. 151-156
Author(s):  
Lihua Gong ◽  
Weimin Guo ◽  
Feng Pan
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Rate ◽  
Base Metal ◽  
Corrosion Behavior ◽  
Welded Joint ◽  
Salt Spray ◽  
Atmospheric Environment ◽  
Cycle Period ◽  
Corrosion Tests ◽  
Immersion Corrosion

Abstract The influence of metal inert-gas arc welding (MIG) on the corrosion behavior of 6061-T6 aluminum alloy in a simulated tropical marine atmospheric environment (related to high temperature, high humidity and high salt spray) were examined by dry-wet alternate immersion corrosion tests. The equivalent conversion was used to design the accelerated test time. The results show that in the initial stage, the intermetallic compound, rich in Fe, Si and Cu, had little influence on corrosion resistance in the heat-affected zone. For a corrosion time of 3 days in a tropical marine atmospheric environment, the corrosion rate of the welded joint increased rapidly, even reaching 3.5 times that of the base metal. Though the corrosion products had significant impact on slowing down the corrosion rate, as with the base metal, the corrosion rate of the welded joint was nearly double that of the base metal during the longest cycle period involving alternate immersion corrosion tests for 20 days.

The Relationship of High Strength Aluminum Alloy Corrosion Behavior and Corrosion Environment

2014 ◽  
Vol 904 ◽  
pp. 86-89
Author(s):  
Song Zhou ◽  
Li Hui ◽  
Liang Xu ◽  
Yu Tong Guo ◽  
Shao Hua Ma
Keyword(s):  
Aluminum Alloy ◽  
High Strength ◽  
Corrosion Damage ◽  
Fuel Tank ◽  
Nacl Solution ◽  
Surface Corrosion ◽  
Corrosion Pit ◽  
Corrosion Pits ◽  
Relationship Of ◽  
The Relationship

The aim of this article is to research the characteristics of corrosion pit on 2xxx aluminum alloys in different environments (3.5wt% NaCl solution, water in fuel tank and wet air). Measure the area of corrosion pit, the depth of corrosion pit in different environments. The results show that in 3.5wt% NaCl solution: the initiation of surface corrosion pits mainly occur in 24h, with time increasing ,the depth of corrosion pit rises indistinctively; in water in fuel tank : during 24h-120h, with the extension of corrosion time, the maximum depth of corrosion pits changed a little, the maximum corrosion area became a little smaller than that in 3.5wt% NaCl solution; in wet air: the corrosion damage was smaller than that in 3.5wt% NaCl solution and water in fuel tank, the depth of the corrosion pit was about 20μm, the biggest size of corrosion pit area was about 0.5 x104μm2.

scholarly journals STUDY ON ALTERNATE IMMERSION CORROSION BEHAVIOR AND MECHANISM OF SDCM DIE STEEL FOR HOT STAMPING

2021 ◽  
Vol 55 (5) ◽  
Author(s):  
Jiang Bin ◽  
Zuo Pengpeng ◽  
Wu Xiaochun
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Hot Stamping ◽  
High Hardness ◽  
Corrosion Damage ◽  
Uniform Corrosion ◽  
Tempering Temperature ◽  
Immersion Corrosion ◽  
Corrosion Pit ◽  
Pit Depth

In this paper, the alternate immersion corrosion test of Cr-Mo-V series SDCM steel for hot stamping was carried out, and different stresses were loaded with self-made fixture. The results shown that regardless of hardness and stress, the corrosion mode of the material is uniform corrosion. Stress could significantly increase the corrosion rate, with lower hardness and higher corrosion rate. Because of the existence of Corrosion Removal Layer (CRL), the maximum corrosion pit depth would be reduced. The maximum corrosion pit depth and Corrosion Pit density (CPD, ρv) were used to describe the degree of corrosion damage. From low to high hardness, the CPD ρv and corrosion resistance increased gradually. With the increased of tempering temperature, the hardness decreased, and the percentage of carbide area in the field of view increased from 16.36% to 24.32%. The irregular spherical carbide M23(C, N)6 rich in Cr coarsens and consumes Cr element in the material, which lead to the decrease of corrosion resistance. Through the polarization curve of the dynamic potential, we known that the current density was increased with the hardness decreased, from 28.53 μA/mm2 to 40.93 μA/mm2.

Corrosion Parameters Distribution Rule and Influence Factors of LY12CZ Aluminum Alloy

2010 ◽  
Vol 139-141 ◽  
pp. 321-325
Author(s):  
Zhi Tao Mu ◽  
Zuo Tao Zhu ◽  
Ding Hai Chen ◽  
Bin Ye
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Corrosion Fatigue ◽  
Influence Factors ◽  
Gumbel Distribution ◽  
Distribution Models ◽  
Accelerated Corrosion ◽  
Corrosion Depth ◽  
Distribution Rule ◽  
Corrosion Pits

The corrosion depth, corrosion area, corrosion pit volume and area of LY12CZ aluminum alloy with different corrosion time were obtained from accelerated corrosion experiment. Four distribution models such as normal, Gumbel, Logistic and double parameter Weibull were used to test their distributions. It can found that the corrosion depth and corrosion area obey Gumbel distribution and the area and volume of corrosion pits obey double parameter Weibull distribution; Choose ten variables as the parameters of influence corrosion fatigue life, through grey relational analyze we can found that the deepest corrosion depth is the biggest influence gene of corrosion fatigue life, and the corrosion grade is an important influence gene almost equal to the deepest depth because it considered the influence of corrosion area and corrosion depth, so we can use it as an parameter to evaluate the calendar life of corrosion conditions.

STUDY ON THE PIT GROWTH DURING CORROSION FATIGUE OF ALUMINUM ALLOY

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3975-3980 ◽  
Author(s):  
S. ISHIHARA ◽  
S. SAKA ◽  
Z. Y. NAN ◽  
T. GOSHIMA ◽  
H. SHIBATA ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Crack Initiation ◽  
Corrosion Fatigue ◽  
Early Stage ◽  
Fatigue Tests ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Corrosion Pit ◽  
Aluminum Alloy 2024 ◽  
Corrosion Pits

Tension-compression and rotating bending fatigue tests were carried out using aluminum alloy 2024-T3 in 3% sodium chloride solution. During corrosion fatigue process, many corrosion pits were initiated at the early stage, and cracks were initiated from the pits. The characteristics of the pit growth were investigated in detail. The critical condition for crack initiation from the corrosion pit was also studied. Crack initiation periods during corrosion fatigue were evaluated on the basis of the corrosion pit growth law.

Sign in / Sign up

Export Citation Format

Share Document