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.

Effect of pre-corrosion and corrosion/fatigue alternation frequency on the fatigue life of 7B04-T6 aluminum alloy

2016 ◽  
Vol 31 (24) ◽  
pp. 3869-3879 ◽  
Author(s):  
Tengfei Cui ◽  
Daoxin Liu ◽  
Jian Cai ◽  
Xiaohua Zhang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Corrosion Fatigue ◽  
Image Position

Abstract

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.

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.

Corrosion mechanism and fatigue behavior of 2A70-T6 aluminum alloy under alternating corrosion and fatigue

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lei Fu ◽  
Hui Li ◽  
Li Lin ◽  
Qingyuan Wang ◽  
Qi Fan ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Corrosion Fatigue ◽  
Intergranular Corrosion ◽  
Fatigue Behavior ◽  
Cumulative Damage ◽  
Corrosion Mechanism ◽  
Corrosive Environment ◽  
Content Type ◽  
Damage Rule

Purpose Most supersonic aircraft were manufactured using 2A70 aluminum alloy. The purpose of this paper is to study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue. Design/methodology/approach For this purpose, the aluminum alloy samples were subjected to pre-corrosion and alternating corrosion-fatigue experiments. The failure mechanisms of corrosion and corrosion fatigue were analyzed using microscopic characterization methods of electrochemical testing, X-ray diffraction and scanning electron microscopy. Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life. Findings The results showed that the corrosion damage caused by the corrosive environment was gradually connected by pitting pits to form denudation pits along grain boundaries. The deep excavation of chloride ions and the presence of intergranular copper-rich phases result in severe intergranular corrosion morphology. During cyclic loading, alternating hardening and softening occurred. The stress concentration caused by surface pitting pits and denudation pits initiated fatigue cracks at intergranular corrosion products. At the same time, the initiation of multiple fatigue crack sources was caused by the corrosion environment and the morphology of the transient fracture zone was also changed, but the crack propagation rate was not basically affected. The polarization curve and impedance analysis results showed that the corrosion rate increases first, decreases and then increases. Fatigue failure behavior was directly related to micro characteristics such as corrosion pits and microcracks. Originality/value In this research, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue. To study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, the Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life.

Modeling of Corrosion Fatigue Life of Stainless Steel Joints Welded by Laser-Metal Active Gas Hybrid Welding

CORROSION ◽  
10.5006/2786 ◽  
2018 ◽  
Vol 74 (10) ◽  
pp. 1132-1140 ◽  
Author(s):  
Tao Yang ◽  
Wei-lin Chen ◽  
Guo-qing Gou ◽  
Hong-lei Tian ◽  
Yong Chen
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Fatigue Life ◽  
Corrosion Fatigue ◽  
Fatigue Testing ◽  
Welding Process ◽  
Hybrid Welding ◽  
Corrosion Properties ◽  
Mechanical Properties And Corrosion ◽  
Corrosion Pits

The mechanical properties and corrosion resistance of the stainless steel (SS) corbel decline sharply after the welding process, which may cause serious accidents. Combining with microcharacteristics, mechanical properties, and corrosion properties, mathematic theories were used and an accurate prediction model of the corrosion fatigue life of SS butt joints produced by laser-metal active gas hybrid welding (LMHW) was established. The joints produced by LMHW have good mechanical properties, with the joint strength coefficient a remarkable 89%. In corrosion fatigue testing, corrosion pits will first appear in the weld seam as a result of the microstructural difference, then cracks initiate. Meanwhile, both the higher NaCl concentration and lower stress ratio will promote the anodic dissolution of metal, leading to the reduction and obscuring of fatigue striation features on the fracture surface. This high-accuracy mathematical modeling can help validate the advanced LMHW method and, in turn, facilitates the manufacture of stainless steel corbels in rail vehicles.

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.

Corrosion–Fatigue Life Prediction for 2024-T62 Aluminum Alloy Using Damage Mechanics-Based Approach

2011 ◽  
Vol 21 (8) ◽  
pp. 1245-1266 ◽  
Author(s):  
W. P. Hu ◽  
Q. A. Shen ◽  
M. Zhang ◽  
Q. C. Meng ◽  
X. Zhang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Corrosion Fatigue ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Salt Spray ◽  
Fatigue Crack Initiation ◽  
Continuum Damage Mechanics ◽  
Fatigue Life Prediction

An approach based on the continuum damage mechanics was applied to predict corrosion–fatigue crack initiation life of 2024-T62 aluminum alloy. A fatigue test in air, a pre-corrosion–fatigue test, and a corrosion–fatigue test on smooth standard specimens were performed. The fatigue lives are strongly reduced by the corrosive environment of 5 wt.% NaCl continuous salt spray compared with non-corroded specimens. Damage evolution models for fatigue in air and pre-corrosion–fatigue of smooth specimens were established, which forms the basis for solving the corrosion–fatigue problem. Finally, the method of corrosion–fatigue life prediction was presented. The predictions comply with the experimental data.

Mechanical and Electrochemical Coupled Pitting Behavior of 2219 Aluminum Alloy: A Theoretical and Experimental Study

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Yuanyang Miao ◽  
Shengli Lv ◽  
T. S. Srivatsan ◽  
Xiaosheng Gao
Keyword(s):  
Aluminum Alloy ◽  
Damage Mechanics ◽  
Mechanical Load ◽  
Theoretical Estimate ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Accelerated Corrosion ◽  
Alloy Chemistry ◽  
Accelerated Corrosion Tests ◽  
Corrosion Pits

Abstract This study attempts to provide a theoretical estimate coupled with an analysis of the measured data to predict pitting damage of an aluminum alloy 2219 under the conjoint influence of mechanical load and corrosive environment. In accordance with the basic principle of crater growth coupled with the synergistic influences of mechanical and chemical effects, the law governing the presence and growth of corrosion pits was studied. Based on the concept of microscopic damage mechanics, porosity as a damage variable was introduced and the resulting model for estimating the reduction in elastic modulus of the material that has experienced observable damage due to pitting was established. Accelerated corrosion tests and uniaxial tensile tests are carried out, and a research-grade microscope coupled with a laser range finder was used to study the formation, presence, and growth of the pits with time. It was found that the corrosion pit in the chosen aluminum alloy can be simulated as a semi-ellipsoid, and the relationship between the depth of the pit and applied stress is an exponential function. This enabled in establishing the influence of alloy chemistry on nature, extent, and severity of damage due to pitting. The macroscopic morphology of the damaged specimens after corrosion was carefully observed and analyzed. The influence of time of exposure to the environment and applied load on damage due to pitting was verified. A comparison between the calculated results and experimental data reveals an overall correctness of the method developed and discussed in this paper.

Sign in / Sign up

Export Citation Format

Share Document