Effect of Aging Treatments on the Tensile Strength and SCC Resistance of 7A04 Aluminum Alloy

2014 ◽  
Vol 490-491 ◽  
pp. 73-77
Author(s):  
Chun Juan Fu ◽  
Mei Yu ◽  
Rong Bao Ma ◽  
Rui Yang Wang ◽  
Jian Hua Liu
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Stress Corrosion ◽  
Corrosion Test ◽  
Constant Load ◽  
Electrochemical Analysis ◽  
Scanning Electron Micrographs ◽  
Nacl Solution ◽  
Corrosion Pits ◽  
Scanning Electron

Effect of different aging treatments(namely AT1, AT2, AT3 and AT4) on the tensile strength(TS) and stress corrosion cracking(SCC) resistance of 7A04 aluminum alloy in 3.5% NaCl+0.5% H2O2solution was investigated using constant load tensile stress corrosion test. Electrochemical behavior of the alloy after different aging treatments was analyzed in 3.5% NaCl solution. The results show that AT1 (i.e. 135°C/16h) increases the TS but decreases the SCC resistance of 7A04. AT2 (i.e. 120°C/7h+165°C/10h) provides the highest SCC resistance and simultaneously retains the TS. AT3 (i.e. 115°C/5h+165°C/10h) decreases both the TS and SCC resistance. The electrochemical analysis indicates that the corrosion resistance of AT2 is the highest, which helps enhance the SCC resistance. The scanning electron micrographs reveal that intergranular corrosion occurs from the corrosion pits on the surface of the specimens when tested under stress, resulting in the ultimate fracture.

Effect of micro-arc oxidation coating on stress corrosion behavior of AA7050

2020 ◽  
Vol 67 (2) ◽  
pp. 178-186
Author(s):  
R.G. Song ◽  
T.S. Hua ◽  
Y. Zong ◽  
S.W. Cai
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Stress Corrosion ◽  
Corrosion Behavior ◽  
Constant Load ◽  
Coated Specimen ◽  
Nacl Solution ◽  
Cracking Behavior ◽  
Content Type ◽  
Micro Arc Oxidation

Purpose This paper aims to study the effect of Micro-arc oxidation (MAO) coating on stress corrosion and electrochemical behavior of aluminum alloy. Design/methodology/approach The stress corrosion cracking behavior of 7050 aluminum alloy (AA7050) after MAO treatment was investigated in 3.5 Wt.% NaCl solution using the constant load ring. Electrochemical impedance spectroscopy (EIS) was used to evaluate the change of corrosion resistance of MAO specimens in 3.5  Wt.% NaCl solution, and appropriate equivalent circuits were established. Findings The results demonstrated that the MAO coating can improve the corrosion resistance of the AA7050 and avoid the reduction of mechanical properties caused by corrosion. In the initial stage of corrosion, the corrosion resistance of coated specimen decreased at first and then increased. In the middle and final stage of corrosion, the corrosion resistance of coated specimen decreased at first and then stabilized. Originality/value The long-term corrosion behavior of MAO specimens under stress was studied by constant load experiment and EIS. It has guiding significance for the application of MAO technology on aluminum alloy.

Study on Mechanical Properties of AA6351 Alloy Reinforced with Titanium Di-Boride (TiB2) Composite by In Situ Casting Method

2015 ◽  
Vol 787 ◽  
pp. 583-587 ◽  
Author(s):  
V. Mohanavel ◽  
K. Rajan ◽  
K.R. Senthil Kumar
Keyword(s):  
Tensile Strength ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Scanning Electron Micrographs ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
In Situ Reaction ◽  
Halide Salts ◽  
Scanning Electron

In the present study, an aluminum alloy AA6351 was reinforced with different percentages (1, 3 and 5 wt %) of TiB2 particles and they were successfully fabricated by in situ reaction of halide salts, potassium hexafluoro-titanate and potassium tetrafluoro-borate, with aluminium melt. Tensile strength, yield strength and hardness of the composite were investigated. In situ reaction between the inorganic salts K2TiF6 and KBF4 to molten aluminum leads to the formation of TiB2 particles. The prepared aluminum matrix composites were characterized using X-ray diffraction and scanning electron microscope. Scanning electron micrographs revealed a uniform dispersal of TiB2 particles in the aluminum matrix. The results obtained indicate that the hardness and tensile strength were increased with an increase in weight percentages of TiB2 contents.

Characterization and Utilization of Coconut Fibers of the Caribbean

2014 ◽  
Vol 1611 ◽  
pp. 95-104 ◽  
Author(s):  
Nadira Mathura ◽  
Duncan Cree ◽  
Ryan P. Mulligan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Micrographs ◽  
Saline Water ◽  
Gauge Length ◽  
Scanning Electron Micrographs ◽  
Coir Fiber ◽  
Coir Fibers ◽  
The Caribbean ◽  
Scanning Electron

ABSTRACTIn many tropical countries coconut (coir) fiber production is a major source of income for rural communities. The Caribbean has an abundance of coconuts but research into utilizing its by-products is limited. Environmentally friendly coir fibers are natural polymers generally discarded as waste material in this region. Research has shown that coir fiber from other parts of the world has successfully been recycled. This paper therefore investigates the mechanical properties of Caribbean coir fiber for potential applications in civil engineering.Approximately four hundred fibers were randomly taken from a coir fiber stack and subjected to retting in both distilled and saline water media. The mechanical properties of both the retted and unretted coir fibers were evaluated at weekly increments for a period of 3 months. Tensile strength test, x-ray diffraction analysis and scanning electron micrographs were used to assess trends and relationships between fiber gauge lengths, diameter, tensile strength and Young’s modulus. Diameters ranged between 0.11 mm-0.46 mm, while fiber samples were no longer than 250 mm in length. The tensile strength and strain at break decreased as the gauge length increased for both unretted and retted fibers. The opposite occurred for the relationship between the gauge length and Young’s modulus. Additionally, the tensile strength and modulus decreased as the fiber diameter increased. Neither distilled nor saline water improved the coir fiber’s crystalline index. Scanning electron micrographs qualitatively assessed fiber surfaces and captured necking and microfibril degradation at the fractured ends.The analysis revealed that the tensile strength, modulus, strain at break and crystallinity properties of the Caribbean coir fibers were comparable to commercially available coir fiber which are currently being used in many building applications.

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.

Effect of pH on Stress Corrosion Cracking of 7050-T7451 Aluminum Alloy in 3.5 wt% NaCl Solution

CORROSION ◽  
1990 ◽  
Vol 46 (6) ◽  
pp. 444-449 ◽  
Author(s):  
W-T. Tsai ◽  
J-B. Duh ◽  
J-J. Yeh ◽  
J-T. Lee ◽  
Y-C. Chang
Keyword(s):  
Aluminum Alloy ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Nacl Solution ◽  
Effect Of Ph

AA-MMA Prepolymer Grafted LLDPE as Compatibilizer for Starch-PE Blends

2011 ◽  
Vol 374-377 ◽  
pp. 170-173
Author(s):  
Li Min Tai
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graft Copolymerization ◽  
Reactive Extrusion ◽  
Scanning Electron Micrographs ◽  
Screw Extruder ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Compatibilization Effect ◽  
Scanning Electron

Through the graft copolymerization of LLDPE and the AA-MMA prepolymer by reactive extrusion on the single-screw extruder, the LLPE-g-AA-MMA was prepared and used as compatibilizer for starch/PE blends, and then the compatibilization effect was investigated. The results exhibited that the addition of this compatibilizer substantially improved the mechanical properties, especially the tensile strength. Scanning electron micrographs of the blend specimens also supported the above observations.

The corrosion behavior of chromated AA2024 aluminum alloy in 3.5% NaCl solution

2019 ◽  
Vol 66 (6) ◽  
pp. 879-887 ◽  
Author(s):  
Yong Zhou ◽  
Pei Zhang ◽  
Jinping Xiong ◽  
Fuan Yan
Keyword(s):  
Aluminum Alloy ◽  
Grain Boundary ◽  
Corrosion Behavior ◽  
Electrochemical Measurement ◽  
Nacl Solution ◽  
Content Type ◽  
Chromate Conversion Coating ◽  
Chromate Coating ◽  
Corrosion Mechanisms ◽  
Corrosion Pits

Purpose A chromate conversion coating was prepared on the surface of bare AA2024 aluminum alloy by direct immersion in the chromating treatment bath, and the corrosion behavior of chromated AA2024 aluminum alloy in 3.5 per cent NaCl solution was studied by electrochemical measurement and microstructural observation. Design/methodology/approach According to the polarization curve test and the scanning electron microscope observation, the corrosion evolution of chromated AA2024 in 3.5 per cent NaCl solution was divided into the following three stages: coating failure, pitting corrosion and intergranular corrosion (IGC). Findings In the first stage, the chromate coating degraded gradually due to the combined action of chloride anions and water molecules, resulting in the complete exposure of AA2024 substrate to 3.5 per cent NaCl solution. Subsequently, in the second stage, chloride anions adsorbed at the sites of θ phase (Al2Cu) and S phase (Al2CuMg) on the AA2024 surface preferentially, and some corrosion pits initiated at the above two sites and propagated towards the deep of crystal grains. However, the propagation of a pit terminated when the pit front arrived at the adjacent grain boundary, where the initiation of IGC occurred. Originality/value Finally, in the third stage, the corrosion proceeded along the continuous grain boundary net and penetrated the internal of AA2024 substrate, resulting in the propagation of IGC. The related corrosion mechanisms for the bare and the chromated AA2024 were also discussed.

scholarly journals Investigation of Mechanical Properties and Salt Spray Corrosion Test Parameters Optimization for AA8079 with Reinforcement of TiN + ZrO2

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5260
Author(s):  
T. Sathish ◽  
V. Mohanavel ◽  
T. Arunkumar ◽  
T. Raja ◽  
Ahmad Rashedi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Ultimate Tensile Strength ◽  
Corrosion Test ◽  
Salt Spray ◽  
Base Material ◽  
Salt Spray Corrosion ◽  
Microhardness Test ◽  
Test Parameters ◽  
Stirring Time

This work mainly focuses on increasing the mechanical strength and improving the corrosion resistance of an aluminum alloy hybrid matrix. The composites are prepared by the stir casting procedure. For this work, aluminum alloy 8079 is considered as a base material and titanium nitride and zirconium dioxide are utilized as reinforcement particles. Mechanical tests, such as the ultimate tensile strength, wear, salt spray corrosion test and microhardness test, are conducted effectively in the fabricated AA8079/TiN + ZrO2 composites. L9 OA statistical analysis is executed to optimize the process parameters of the mechanical and corrosion tests. ANOVA analysis defines the contribution and influence of each parameter. In the tensile and wear test, parameters are chosen as % of reinforcement (3%, 6% and 9%), stirring speed (500, 550 and 600 rpm) and stirring time (20, 25 and 30 min). Similarly, in the salt spray test and microhardness test, the selected parameters are: percentage of reinforcement (3%, 6% and 9%), pH value (3, 6 and 9), and hang time (24, 48 and 72 h). The percentage of reinforcement highly influenced the wear and microhardness test, while the stirring time parameter extremely influenced the ultimate tensile strength. From the corrosion test, the hang time influences the corrosion rate. The SEM analysis highly reveals the bonding of each reinforcement particle to the base material.

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