scholarly journals STUDI EXPERIMENTAL FATIK KOROSI ALUMINIUM PADUAN 7075-T6 PADA LINGKUNGAN 3,5% NaCl DENGAN INHIBITOR Na2CrO4

POROS ◽  
2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Priyani Budiyarti Budiyarti
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Rate ◽  
Fatigue Testing ◽  
Fatigue Cracking ◽  
Aircraft Industry ◽  
Good Resistance ◽  
Microstructure Observation ◽  
Corrosion Propagation ◽  
Optical Microstructure ◽  
Rate Test

AA7075-T6 aluminum alloy is a material that widely used in the aircraft industry because aluminum as a lightweight metal, good machinability, good corrosion resistance and good castability and non-magnetic metals. Aluminum also has high tenacity, is easy to form and is easy to connect. Aluminum has good resistance to corrosion, however aluminum has effect to corrosion if it is on corrosive environment including AA7075-T6 aluminum alloy which used in the aircraft industry. Inhibitor is used to control a corrosion. The aims of these researchs were to investigate the effect of inhibitors on corrosion rates and the rate of fatigue crack corrosion propagation on AA7075-T6 aluminum alloys. This research is used Na2CrO4 inhibitors with variety of concentrations of 0.1%, 0.3%, 0.5% and 0.7% added to 3.5% NaCl solution. Corrosion rate test is used a method of potential dynamic polarization. Corrosion fatigue testing is carried out with constant amplitude at a frequency of 10 Hz and a voltage ratio (R) 0.1. Specimens were used cracked specimen centers (CCT) on orientation in the direction of rolling. The supporting data of the research were the mechanical properties of the material included optical microstructure observation, tensile testing and hardness testing. The results have shown that the optimal concentration of Na2CrO4 inhibitors was achieved at 0.5% which was characterized by a decreasing in corrosion rate and slower corrosion rate of fatigue cracking.

SEM In Situ Study on Pre-Corrosion and Fatigue Cracking Behavior of LY12CZ Aluminum Alloy

2012 ◽  
Vol 525-526 ◽  
pp. 81-84 ◽  
Author(s):  
Xu Dong Li ◽  
Zhi Tao Mu ◽  
Zhi Guo Liu
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Fatigue ◽  
Fatigue Cracking ◽  
Corrosion Damage ◽  
Experimental Investigations ◽  
Aircraft Industry ◽  
Cracking Behavior ◽  
Corrosion Pit ◽  
Scanning Electron

Corrosion fatigue is a form of degradation subjected to combined damage of mechanical stress and corrosive medium, which is an issue in aircraft industry. Experimental investigations on prior corrosion fatigue cracking behavior of LY12CZ were conducted with scanning electron microscope (SEM). Results indicate corrosion damage is important for the fatigue small cracking behavior of LY12CZ aluminum alloy. The effect of corrosion pit on fatigue crack can be characterized by the depth of corrosion pit. Based on small crack, another way to evaluate crack growth rate for AALY12CZ is proposed.

UNS A97075

Alloy Digest ◽  
1986 ◽  
Vol 35 (7) ◽  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminum Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Good Resistance ◽  
Temperature Performance ◽  
Structural Applications ◽  
Structural Parts ◽  
Very High

Abstract UNS No. A97075 is a wrought precipitation-hardenable aluminum alloy. It has excellent mechanical properties, workability and response to heat treatment and refrigeration. Its typical uses comprise aircraft structural parts and other highly stressed structural applications where very high strength and good resistance to corrosion are required. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on low temperature performance as well as forming, heat treating, and machining. Filing Code: Al-269. Producer or source: Various aluminum companies.

Stress Corrosion Cracking Behaviour of Flux Bounded TIG Welded AA2219 T87 Aluminum Alloy in 3.5 Weight Percent NaCl Solution

2015 ◽  
Vol 766-767 ◽  
pp. 733-738
Author(s):  
A.V. Santhana Babu ◽  
P.K. Giridharan ◽  
A. Venugopal ◽  
P. Ramesh Narayanan ◽  
S.V.S. Narayana Murty
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Weight Percent ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Nacl Solution ◽  
Test Technique ◽  
Rate Test

Limitation in penetration depth is a concern in conventional TIG welding. To improve penetration capability of TIG process, Flux Bounded TIG (FBTIG) has been developed. Stress corrosion cracking (SCC) behavior of FBTIG welds of aluminum alloy AA 2219 T87 is evaluated in 3.5 weight percent NaCl solution using Slow Strain Rate Test technique (SSRT) as per ASTM G129. SCC index defined as the ratio of the elongation of tensile tested specimen in NaCl to that of air is taken as a measure of the susceptibility to cracking. Based on the SCC index, it is concluded that the SCC resistance of FBTIG joints are good and comparable to that of conventional TIG welds.

scholarly journals Effect of Heat Treatment and Sulfuric Acid Anodization on Corrosion Resistance of Aluminum Alloy (AA7075)

2021 ◽  
Vol 40 (1) ◽  
pp. 56-62
Author(s):  
M. Abdullahi ◽  
L.S. Kuburi ◽  
P.T. Zubairu ◽  
U. Jabo ◽  
A.A. Yahaya ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Polarization Resistance ◽  
Testing Machine ◽  
Palm Kernel ◽  
Engine Oil ◽  
Micro Hardness

This paper, studied the effect of heat treatment and anodization on corrosion resistance of aluminum alloy 7075 (AA7075), with a view to improving its corrosion resistance. Microstructure and micro hardness of the anodic film of the samples were studied with the aid of optical metallurgical microscope and automated micro hardness testing machine. Linear polarization methods were used to assess the corrosion behaviour of the alloy in 0.5M HCl. The microstructure of the annealed sample showed formation of dendrites while precipitation hardened samples in palm kernel oil and SAE 40 engine oil showed precipitates of MgZn2. The SEMS result showed pores and micro cracks on the surfaces of the anodized samples, with the as cast and anodized sample in sulfuric acid exhibiting most compact with few pores. The as cast and sulfuric acid anodized sample shows highest micro hardness value of 205.33 HV, while the least value of 150.67 HV was recorded in sample precipitation hardened in SAE 40 engine oil and anodized in sulfuric acid. Analysis of the potentiodynamic polarization data and curves showed a linear relationship (decrease in icorr, decreases the corrosion rate) between current density and the corrosion rate in all the samples. Higher polarization resistance of 15.093 Ω/cm2 was recorded by the as cast and Sulfuric acid (SA) anodized sample while the precipitation treated in SAE 40 engine oil plus SA anodized sample recorded lowest polarization resistance of 5.2311 Ω/cm2. Heat treatment alone improves corrosion resistance of AA 7075 in 0.5 M HCl solution but heat treatment plus SA anodization does not improve corrosion resistance in the same environment.

scholarly journals Corrosion Rate of Aluminum Alloy in Moving Sodium Chloride Solution

1998 ◽  
Vol 47 (4) ◽  
pp. 254-259 ◽  
Author(s):  
Yasuyuki Takatani ◽  
Tsuyoshi Masugata ◽  
Kazuo Fujiwara ◽  
Koichi Shinkai ◽  
Koichi Hayashi
Keyword(s):  
Aluminum Alloy ◽  
Sodium Chloride ◽  
Corrosion Rate ◽  
Chloride Solution ◽  
Sodium Chloride Solution

Research on the Influence of Salt Fog Corrosion Behavior of 6005A Aluminum Alloy Welded Joints by Environment Humidity

2013 ◽  
Vol 662 ◽  
pp. 251-257
Author(s):  
Ning Xia ◽  
Zhi Min Zhu ◽  
Hui Chen
Keyword(s):  
Weight Loss ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Relative Humidity ◽  
Corrosion Rate ◽  
Environmental Humidity ◽  
Welding Joints ◽  
Salt Fog Corrosion ◽  
Salt Fog

6005A aluminum alloys were welded at different relative humidity conditions. The effects of relative humidity on the salt fog corrosion of the welding joints were researched. The results showed that the weight loss of the joints after 14 days corrosion was higher than that corroded after 7days, but the corrosion rate was lower. The corrosion rate first increased then declined with the increase of environmental humidity for the joints corroded for 7days. However, when the environmental humidity was 80%, corrosion rate achieved the maximum, when environment humidity was 70%, corrosion rate was the lowest. After corroded for 14 days, corrosion rate was the maximum when the environmental humidity was 50%, and it was the lowest when the environmental humidity was 90%. The tensile strength declined obviously after corrosion.

Damage and Thixotropy in Asphalt Mixture and Binder Fatigue Tests

2012 ◽  
Vol 2293 (1) ◽  
pp. 8-17 ◽  
Author(s):  
Félix Pérez-Jiménez ◽  
Ramon Botella ◽  
Rodrigo Miró
Keyword(s):  
Cyclic Loading ◽  
Strain Amplitude ◽  
Fatigue Testing ◽  
Complex Modulus ◽  
Asphalt Mixture ◽  
Viscoelastic Behavior ◽  
Fatigue Cracking ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Irreversible Damage

Fatigue cracking is considered one of the main damage mechanisms in asphalt pavement design. Design methods use fatigue laws obtained by laboratory testing of the materials involved. Typically, these tests consist of subjecting the asphalt mixture to cyclic loading until failure occurs. However, failure is associated not with specimen fracture (which is unusual), but with a slight decrease in the mechanical properties of the material, usually in the complex modulus. As a consequence, it is important to differentiate between real damage to the material and changes in its viscoelastic behavior and thixotropy. It is also crucial to account for the healing that occurs in asphalt material after rest periods. The above considerations are important in the fatigue testing of asphalt binders because these materials show pronounced viscoelastic behavior and thixotropy, especially when subjected to cyclic loading. This paper demonstrates that in many cases what is taken for fatigue failure during testing (i.e., a decrease in the complex modulus below half of its initial value) is actually thixotropy. Thus, the complex modulus can be recovered by reducing the loading or, as in this study, the strain applied. In contrast, asphalt mixtures experience irreversible damage, and depending on the asphalt binder, the thixotropic effects are more or less pronounced. This paper analyzes the failure criteria currently used in the fatigue testing of asphalt mixtures and binders and evaluates the parameters chosen, namely, complex modulus (G*) and phase angle (δ) to characterize asphalt binders (G*sin δ). A cyclic uniaxial tension–compression test under strain-controlled conditions was performed. Three test modalities were used: time sweeps (constant strain amplitude until total failure), increasing strain sweeps (increase in strain amplitude every 5,000 cycles), and up-and-down strain sweeps (alternating increases and decreases in strain amplitude).

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.

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