scholarly journals Effects of Aging Treatment on Corrosion Behavior of a Tensile Deformed Al-Cu-Mn-Fe-Zr Alloy in 3.5% NaCl Solution

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5062
Author(s):  
Qing Tian ◽  
Qiu-Mei Yang ◽  
Yong-Cheng Lin ◽  
Jun-Quan Wang ◽  
Xu-Hao Zhu
Keyword(s):  
Corrosion Resistance ◽  
Grain Boundaries ◽  
Aging Time ◽  
Pitting Corrosion ◽  
Resistance Mechanism ◽  
Aging Treatment ◽  
Corrosion Current ◽  
Potential Difference ◽  
Aged Alloy ◽  
Zr Alloy

In this paper, the effects of an aging treatment on the corrosion resistance/mechanism of a tensile deformed Al-Cu-Mn-Fe-Zr alloy are investigated. The impedance magnitude and polarization resistance increase, while the corrosion current decreases with the increased aging time and temperature. The discontinuously-distributed precipitates and precipitation-free zone, which can cut the corrosion channels, appear at grain boundaries when the temperature is relatively high and the aging time is relatively long. They can improve the corrosion resistance. Additionally, the intergranular and pitting corrosion are the main mechanisms. The intergranular corrosion is likely to occur in an under-aged alloy. This is because the potential difference between the grain boundaries and grains is high, due to the segregation of Cu atoms. When the aging degree is increased, the grain boundary precipitates reduce the potential difference, and the intragranular precipitates make the surrounding matrix prone to dissolution. As such, the pitting corrosion is likely to occur in the over-aged alloys.

Effect of Annealing and Aging Treatment on Pitting Corrosion Resistance of Fine-Grained Mg-8%Al-0.5%Zn Alloy

JOM ◽  
2019 ◽  
Vol 71 (12) ◽  
pp. 4758-4768 ◽  
Author(s):  
Gajanan M. Naik ◽  
S. Narendranath ◽  
S. S. Satheesh Kumar ◽  
Sandeep Sahu
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Aging Treatment ◽  
Fine Grained ◽  
Pitting Corrosion Resistance ◽  
Zn Alloy

Investigation on the Influence of Precipitated Phase on Corrosion Resistance of the Ni-Based Alloys

2012 ◽  
Vol 184-185 ◽  
pp. 1038-1043
Author(s):  
Xue Hui Zhao ◽  
Zhen Quan Bai ◽  
Yao Rong Feng ◽  
An Qing Fu
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Corrosion Resistance ◽  
Electron Microscope ◽  
Grain Boundaries ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
Different Temperatures ◽  
Metallographic Observation ◽  
Precipitated Phases

The influence of precipitated phases in Ni-based alloys during solid solution aging treatment on the performance of Ni-based alloys was investigated by means of metallographic observation, scanning electron microscope (SEM), and transmission electron microscope (TEM). The variation of microstructure and resultant phases as a result of solid solution aging treatment at different temperatures was discussed. The results show that the heat treatment temperature has significant influences on the type as well as quantity of precipitation phases. Lots of phases precipitated at grain boundaries, the distribution of precipitated phases are characterized by mesh-like structure. The corrosion tests results indicate that there is a potential difference between grains and grain boundaries due to the precipitation of chrome carbide at grain boundaries, resulting in pitting corrosion occurred preferentially at grain boundaries, consequently, the corrosion resistance of Ni-based alloys is reduced. In order to enhance the corrosion resistance of Ni-based alloys, it is expected to control the carbon content in a lower range and proper heat treatment process to avoid large amount precipitation of chrome carbide.

Effect of heat treatment on microstructure and corrosion resistance of extruded ZK80 Mg alloy

2019 ◽  
Vol 9 (9) ◽  
pp. 1092-1099
Author(s):  
Fenghong Cao ◽  
Chang Chen ◽  
Zhenyu Wang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Aging Time ◽  
Room Temperature ◽  
Aging Treatment ◽  
Corrosion Process ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Corrosion Properties

The corrosion characteristics and corrosion mechanism of the extruded ZK80 alloy with different states soaking in 3.5% NaCl solution at room temperature were analyzed via OM, SEM, EDS, XRD and static weightlessness method and other experimental analysis methods. The results show that when the aging temperature is constant, and the corrosion rate decreases with the lengthen of aging time, while when the corrosion time is constant, the corrosion rate increases with the increase in aging time. Appropriate aging treatment not only refines the grain of the alloy, but also precipitates the Mg–Zn phase which can effectively prevent the corrosion process and improve the anti-corrosion properties of the alloy. The main corrosion characteristics of the alloy are filamentary corrosion and pitting corrosion.

Preparation and Properties of Fluoride-Coated Mg-Zn-Zr Alloy for Biodegradable Intravascular Stents

2011 ◽  
Vol 287-290 ◽  
pp. 1970-1975
Author(s):  
Xin Yu Ye ◽  
Min Fang Chen ◽  
De Bao Liu ◽  
Meng Yang ◽  
Jun Wei
Keyword(s):  
Corrosion Resistance ◽  
Fine Particles ◽  
Corrosion Current ◽  
Cell Number ◽  
Electrochemical Tests ◽  
In Vitro Biocompatibility ◽  
Intravascular Stents ◽  
Surface Morphologies ◽  
Zr Alloy

In order to improve the corrosion resistance, the samples made of Mg-Zn-Zr alloy were immersed in 20% or 40% hydrofluoric acid (HF) aqueous solutions for different intervals to prepare magnesium fluoride (MgF2) coating on the surface. By comparing the surface morphologies, the samples immersed in 20% HF solution for 6 h on which fine particles in nanoscale covered was selected for the further study. Immersion and electrochemical tests showed that the dense MgF2 coating would improve the corrosion resistance of Mg-Zn-Zr alloy. The corrosion current density (icorr) decreased from 2.10 μA·cm-2 to 0.05 μA·cm-2. The influence of HF treatment on the cytocompatibility was evaluated in vitro. There were significant differences in the cell number between the naked and coated samples after culturing for 3 and 5 days (p<0.05). All the results demonstrate that HF treatment is a promising approach to improve the corrosion resistance and in vitro biocompatibility of Mg-Zn-Zr alloy used as intravascular stents.

The Effect of Hydrogen on Pitting Corrosion of Superaustenitic and Austenitic-Ferritic Stainless Steels

2012 ◽  
Vol 326-328 ◽  
pp. 620-625 ◽  
Author(s):  
Joanna Michalska
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Corrosion Current Density ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Passive Films ◽  
Cyclic Polarization ◽  
Film Stability ◽  
Ferritic Stainless Steels

Hydrogen entering into steel affects its electrochemical properties and may enhance the susceptibility to environmental degradation. The present work has been aimed at further clarifying the effect of hydrogenation on the corrosion behaviour and passivity of highly-alloyed stainless steels. The results were discussed by taking into account hydrogen charged samples and without hydrogen. The corrosion resistance to pitting was qualified with the cyclic polarization curves. The conclusion is that hydrogen may deteriorated the passive film stability and corrosion resistance to pitting of highly-alloyed stainless steel. Furthermore, the presence of hydrogen in passive films increases corrosion current density, decreasing the potential of the film breakdown and repassivation potential. It was also found that the degree of susceptibility to hydrogen-enhanced pitting corrosion was dependent on the type of steel.

Influences of Aging Precipitation on Corrosion Resistance of 18Cr-18Mn-2Mo-0.77N HNS

2009 ◽  
Vol 79-82 ◽  
pp. 1013-1016 ◽  
Author(s):  
Zu Rui Zhang ◽  
Hua Bing Li ◽  
Zhou Hua Jiang ◽  
Zhen Li ◽  
Bao Yu Xu
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Volume Fraction ◽  
Aging Treatment ◽  
High Nitrogen ◽  
Aging Precipitation ◽  
Pitting Corrosion Resistance ◽  
Nitrogen Steel ◽  
The Matrix ◽  
Nose Temperature

Influences of aging precipitation of Cr2N and Chi (χ) phases on the resistance to pitting corrosion and intergranular corrosion of 18Cr-18Mn-2Mo-0.77N high nitrogen steel (HNS) as a type of fundamental and structural materials were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) pattern and electrochemical methods. Intergranular, cellular Cr2N and χ phases precipitate gradually along grain boundaries and inward grains. The volume fraction of precipitation presents a C-curve with a nose temperature of 850°C during 2h aging treatment. The solution-treated (ST) HNS exhibits the highest pitting corrosion potential because of high nitrogen content in steel, and especially no precipitation. The pitting corrosion resistance of aged HNS decreases because of the formation of aging precipitation which results in the depletion of Cr and Mo in the matrix. The pitting corrosion potentials firstly decrease then increase as the same tendency as the amount of precipitation expect 850°C and 900°C. Double loop electrochemical potentiokinetic reaction (DL-EPR) results show that the change tendency of IGC susceptibility is well consistent with the amount of precipitation of aged HNS for 2h at various temperatures. With prolonging the aging time at 850°C, aged HNS presents more obviously intergranular sensitization due to the formation of aging precipitation which results in the depletion of Cr and Mo.

Influence of Various Heat Treatment on Corrosion Resistance of As-Extruded Mg-9Li-3Al-2.5Sr Alloys

2014 ◽  
Vol 788 ◽  
pp. 41-44 ◽  
Author(s):  
Yuan Qing Yu ◽  
Xiao Dong Peng ◽  
Hong Yu Yi ◽  
Jun Wei Liu
Keyword(s):  
Corrosion Resistance ◽  
Intermetallic Compounds ◽  
Unit Volume ◽  
Aging Treatment ◽  
Corrosion Current ◽  
Immersion Test ◽  
Corrosion Process ◽  
Nacl Solution ◽  
Boundary Area ◽  
Solution Treated

The corrosion behavior of Mg-9Li-3Al-2.5Sr alloy, solution treated at 400°C for 3h with various aging temperature (Ta; Ta=75,100,125,150,175°C), was investigated in 3.5% NaCl solution by immersion test and polarization curve measurement. Experimental results suggest that the alloy aged at150°Cfor 6h exhibits the highest corrosion resistance while the alloy treated at 75°C for 6h presents lowermost corrosion resistance. The corrosion resistance of the alloy is related to the grain size and the distribution of Al4Sr compound. The segregation of intermetallic compounds can accelerate the corrosion process. It was found that duo to the proper solid-solution and aging treatment, intermetallic compounds were distributed evenly along the grain boundaries, which can reduce the corrosion rate and corrosion current. In addition,with the growth of grain, the decrease of the grain boundary area per unit volume lead to improvement of corrosion resistance of the alloys.

scholarly journals Enhancing the Corrosion Resistance and Mechanical Properties of a High-Alloying Al-Zn-Mg-Cu-Zr Alloy by Ce Addition and Aging Treatment

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1318
Author(s):  
Xinxiang Yu ◽  
Zhiguo Zhao ◽  
Dandan Shi ◽  
Xiaoyan Dong ◽  
Xianli Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Grain Boundary ◽  
Aging Treatment ◽  
High Strength ◽  
Cu Content ◽  
High Temperature Aging ◽  
Temperature Aging ◽  
Subsequent Incorporation ◽  
Zr Alloy

The corrosion resistance (exfoliation corrosion and inter-granular corrosion) and mechanical properties (strength and hardness) of a high-alloying Al-Zn-Mg-Cu-Zr alloy were improved by the synergistic effect of Ce addition and aging treatment. Ce addition promotes the morphology change of grain boundary precipitates from continuous form to discontinuous form at T6 temper. But the Cu content in grain boundary precipitates became much lower than that in Ce-free alloy, owing to a large amount of Cu being trapped in AlCuCe phase. Hence retrogression and re-aging (RRA) treatment were then adopted. The Cu content in grain boundary precipitates was improved, which can be attributed to the removal of Cu from solid solution during high temperature aging and its subsequent incorporation into grain boundary precipitates. In addition, the size and the distribution discontinuity of the grain boundary precipitates can be further increased and the main intra-grain phases of RRA alloy are still fine η′ phase similar to T6 temper. Therefore, the alloy at RRA temper obtains the optimal corrosion resistance without loss of high strength.

scholarly journals Effect of Vapor Pressure During the Steam Coating Treatment on Structure and Corrosion Resistance of the Mg(OH)2/Mg-Al LDH Composite Film Formed on Mg Alloy AZ61

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1659 ◽  
Author(s):  
Kae Nakamura ◽  
Yuta Shimada ◽  
Tomohiro Miyashita ◽  
Ai Serizawa ◽  
Takahiro Ishizaki
Keyword(s):  
Corrosion Resistance ◽  
Vapor Pressure ◽  
Pitting Corrosion ◽  
Corrosion Current ◽  
Interlayer Distance ◽  
Water Molecules ◽  
Vapor Pressures ◽  
Corrosion Resistant ◽  
High Vapor ◽  
Double Hydroxide

Corrosion resistant films with almost the same film thickness were prepared on the magnesium alloy AZ61 by steam coating at different vapor pressure and treatment times. The effect of the vapor pressure on the structures and the corrosion resistance of the films was investigated by using FE-SEM, SEM-EDX, GAXRD, and potentiodynamic polarization curve measurements in a 3.5 mass percentage NaCl aqueous solution. These studies clarified that the interlayers of Mg-Al Layered Double Hydroxide (LDHs) increased and its structure became non-uniform with an increase in the vapor pressure. The corrosion current density slightly increased with an increase in the vapor pressure during the treatment, but pitting corrosion occurred at both low and high vapor pressures. These results indicate that water molecules were pushed into an interlayer of Mg-Al LDHs by high vapor pressure. Consequently, the interlayer distance of Mg-Al LDH was widened and the cracks were generated in the anti-corrosive film. On the other hand, the Mg-Al LDH with an insufficiently large interlayer distance could not fill the cracks in the Mg(OH)2 crystallites and caused pitting corrosion when the vapor pressure was low.

scholarly journals Effect of Magnesium Addition on Corrosion Resistance of Aluminum -17%Silicon Alloy

2017 ◽  
Vol 12 (4) ◽  
pp. 50-58
Author(s):  
Muna Khethier Abbass ◽  
Khairia Salman Hassan ◽  
Kayser Aziz Ameen
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Electrochemical Behavior ◽  
Die Casting ◽  
Corrosion Current ◽  
Nacl Solution ◽  
Magnesium Metal ◽  
Pitting Corrosion Resistance ◽  
Mg Content

The electrochemical behavior of Al-17%Si alloy is investigated in 3.5wt% NaCl solution. Many alloys with addition of the different wt% magnesium metal of  1wt%, 2%, 3wt% ,4.5wt% ,and 9wt% were prepared by gravity die casting . The microstructures of prepared alloys were examined by optical and SEM microscopes. Corrosion behavior was investigated by using potentiostat instrument under static potentials test and corrosion current was recorded to determine corrosion resistance of all prepared samples. It was found that the addition of Mg metal improves the corrosion resistance of Al-17%Si alloy in 3.5%NaCl solution. The alloy containing 1%Mg shows less corrosion rate than the others while the alloys containing 4.5%Mg, 9%Mg content have the better pitting corrosion resistance than other alloys.

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