Effects of chemical composition on the corrosion behavior of A7N01S-T5 Al alloys

2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540025 ◽  
Author(s):  
Xiaomin Wang ◽  
Xiaoyao Liao ◽  
Chuanping Ma ◽  
Shufang Zhang ◽  
Yan Liu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Corrosion Behavior ◽  
Corrosion Current ◽  
Al Alloys ◽  
Chemical Compositions ◽  
Al Alloy ◽  
Electrochemical Test ◽  
Electrochemical Behaviors ◽  
Cu Content ◽  
Corrosion Pits

Corrosion behavior of 7N01 Al alloy is sensitive to chemical composition. In this paper, stress corrosion cracking (SCC) and electrochemical behaviors of A7N01S-T5 Al alloys with three different chemical compositions were investigated. The corrosion weight loss and corrosion pits depth statistics showed that Alloy #3 (4.53 wt .% Zn , 1.27% Mg , < 0.001% Cu , 0.24% Cr , 0.15% Zr ) possesses the best anti-SCC property, while Alloy #1 (4.54% Zn , 1.09% Mg , 0.102% Cu , 0.25% Cr , 0.15% Zr ) was the weakest one. The different SCC susceptibility was mainly related to the Cu content as Alloy #3 contains higher Cu than Alloys #1 and #2. Electrochemical test result showed that Alloy #3 has higher corrosion potential and lower corrosion current density than Alloys #1 and #2. It is believed that a trace Cu can significantly improve the SC resistance of Al alloy, mainly because that Cu element can reduce the potential difference between grain inside and grain boundaries.

Microstructural analysis and corrosion behavior of Fe, B, and Fe-B-modified Cu-Zn-Al shape memory alloys

2017 ◽  
Vol 35 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Kenneth Kanayo Alaneme ◽  
Eloho Anita Okotete ◽  
Michael Oluwatosin Bodunrin
Keyword(s):  
Corrosion Behavior ◽  
Microstructural Analysis ◽  
Corrosion Current ◽  
Al Alloys ◽  
Electrochemical Technique ◽  
Al Alloy ◽  
Casting Method ◽  
Sem Images ◽  
Current Densities ◽  
Corrosion Mechanisms

AbstractThe corrosion behavior of Cu-Zn-Al alloys modified with Fe, B, and Fe-B was investigated. This was motivated by the need to verify the effect of microalloy additions on the corrosion behavior of Cu-Zn-Al alloys, which, as recent study suggests, impacts microstructural changes other than grain refinement. Cu-Zn-Al alloys were produced by casting method with and without the addition of microalloy elements. The alloys were subjected to thermomechanical treatment before machining of test samples for corrosion and microstructural analysis. Scanning electron microscopy (SEM) and polarization electrochemical technique were used for the study. From the results, increase in grain size and change in grain edge morphology was apparent for the modified Cu-Zn-Al alloys produced. In 3.5 wt.% NaCl and 0.3 m H2SO4 solutions, the corrosion current densities were dependent on the type and concentration of the microalloy addition. Essentially, the corrosion rates for the modified alloys were higher in 3.5 wt.% NaCl solution; in 0.3 m H2SO4 solution, the modified Cu-Zn-Al alloy grades were observed to be more resistant to corrosion. The corrosion mechanisms of the alloys in both solutions were not feasibly established from the SEM images, but the extent of corrosion product deposition was apparent.

An Effective Method to Fabricate 5083 Aluminum Alloy with Excellent Corrosion Resistance

2017 ◽  
Vol 898 ◽  
pp. 1300-1304
Author(s):  
Peng Fei Wang ◽  
Chen Bin Liu ◽  
Jin Chuan Jie ◽  
Ting Ju Li
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Corrosion Behavior ◽  
Corrosion Current ◽  
Optical Microscope ◽  
Electrochemical Test ◽  
Cryogenic Rolling ◽  
Before And After ◽  
Room Temperature Rolling ◽  
5083 Aluminum Alloy

The 5083 aluminum alloy was prepared and subjected to cryogenic rolling (CR) after heat treatment. The samples were reduced from 15mm to 1.5 mm in the thickness direction and the amount of deformation was 90%. For comparison, samples with the same deformation amount were obtained by room temperature rolling (RTR). The corrosion behavior of CR and RTR samples was measured by electrochemical test, and their microstructures before and after corrosion had been studied through electron scanning microscopy (SEM) and optical microscope (OM). The influence of cryogenic rolling on the corrosion behavior of 5083 aluminum alloys was explored. The experiment results suggested that anti-corrosion ability of 5083 aluminum alloys could be enhanced through cryogenic rolling. The corrosion potential elevated and the corrosion current density reduced according to the electrochemical test. The primary reasons and corresponding mechanism were also discussed.

scholarly journals Pitting Corrosion Behavior and Surface Microstructure of Copper Strips When Rolled with Oil-in-Water Emulsions

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7911
Author(s):  
Xudong Yan ◽  
Jianlin Sun
Keyword(s):  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Surface Defects ◽  
Interactive Effect ◽  
Rolling Direction ◽  
Corrosion Current ◽  
Surface Microstructure ◽  
Oil In Water ◽  
Current Densities ◽  
Corrosion Pits

Copper strips experience severe corrosion when rolled with an oil-in-water (O/W) emulsions lubricant. The effects of rolling reduction on the pitting corrosion behavior and surface microstructure of Cu strips were studied in detail using electrochemical measurements and electron back scattered diffraction (EBSD) analysis. It was found that the corrosion current densities of the rolled Cu strips increased with accumulated reduction, which also lowered the pitting potentials and weakened their corrosion resistances. Therefore, the corrosive tendency of Cu strips under different rolling reductions (ε) followed the order of ε0% < ε20.7% < ε50.6% < ε77.3%. The Cu surface easily reacted with chlorine, sulfur, and carbon components from O/W emulsions to generate pitting corrosion. Under the interactive effect of pitting corrosion and stress corrosion, pits expanded along the rolling direction. The aggregation of anions in surface defects, such as dislocations, metastable pits, and microcracks, further accelerated the pitting corrosion of the surface.

scholarly journals Metallurgical Preparation of Nb–Al and W–Al Intermetallic Compounds and Characterization of Their Microstructure and Phase Transformations by DTA Technique

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 2001
Author(s):  
Tomas Cegan ◽  
Daniel Petlak ◽  
Katerina Skotnicova ◽  
Jan Jurica ◽  
Bedrich Smetana ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Intermetallic Compounds ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Al Alloys ◽  
Vacuum Induction Melting ◽  
Al Alloy ◽  
Induction Melting ◽  
Arc Melting

The possibilities of metallurgical preparation of 40Nb-60Al and 15W-85Al intermetallic compounds (in at.%) by plasma arc melting (PAM) and vacuum induction melting (VIM) were studied. Both methods allow easy preparation of Nb–Al alloys; however, significant evaporation of Al was observed during the melting, which affected the resulting chemical composition. The preparation of W–Al alloys was more problematic because there was no complete re-melting of W during PAM and VIM. However, the combination of PAM and VIM allowed the preparation of W–Al alloy without any non-melted parts. The microstructure of Nb–Al alloys consisted of Nb2Al and NbAl3 intermetallic phases, and W–Al alloys consisted mainly of needle-like WAl4 intermetallic phase and Al matrix. The effects of melting conditions on chemical composition, homogeneity, and microstructure were determined. Differential thermal analysis was used to determine melting and phase transformation temperatures of the prepared alloys.

Influence of Triethylamine Inhibitor Addition on the Sealing Process of 6063 Al Alloy

2012 ◽  
Vol 538-541 ◽  
pp. 230-234
Author(s):  
Hui Cheng Yu ◽  
Xiao Xiao Huang ◽  
Yan Yan Han ◽  
Dong Ping Wei
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Al Alloy ◽  
Test Results ◽  
Electrochemical Test ◽  
Tafel Polarization ◽  
Electrochemical Parameters ◽  
6063 Al Alloy

To improve the corrosion resistance of Al alloy, triethylamine (TEN) was added into the sealing solutions. Tafel polarization and electrochemical impedance spectroscopy(EIS) techniques were used to investigate the electrochemical behavior of sealing coatings formed in different concentrations of triethylamine(TEN). Compared with the coatings with D. I. water and the bare aluminum alloy, the polarization curves show that the sealing coatings formed in 5.0 – 7 .0 g.L-1 triethylamine (TEN) solutions have more positive corrosion potential (Ecorr) and pitting corrosion potential (Epit), and lower corrosion current density (icorr). Electrochemical parameters of EIS indicate that the sealing coatings have higher corrosion resistance. The electrochemical test results show the prepared sealing coatings have better corrosion resistance.

scholarly journals Initial Corrosion Behavior of 12Cr1MoV Steel in Thiosulfate-Containing Sodium Aluminate Solution

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1283
Author(s):  
Jingjiu Yuan ◽  
Chaoyi Chen ◽  
Junqi Li ◽  
Bianli Quan ◽  
Yuanpei Lan ◽  
...  
Keyword(s):  
Corrosion Product ◽  
Corrosion Behavior ◽  
Corrosion Current ◽  
Sodium Aluminate ◽  
Corrosion Mechanism ◽  
Alumina Production ◽  
Aluminate Solution ◽  
Corrosion Product Film ◽  
Product Film ◽  
Corrosion Pits

When alumina is produced by the Bayer process with high-sulfur bauxite, the sulfur would strongly corrode the 12Cr1MoV steel made heat exchanger. This study investigated the initial corrosion behavior of the 12Cr1MoV steel exposed to a thiosulfate-containing sodium aluminate (TCSA) solution under the evaporation conditions of alumina production. The obtained corrosion rate equation is V = 6.306·t·exp(−0.71). As corrosion progressed, with the corrosion product film growing, the corrosion current density declines slowly, and the corrosion resistance of the steel is increased. At 1–3 days, the corrosion product film consisted of FeO, Fe2O3, and FeOOH. S2O32− lead to corrosion in local areas of the steel and pits appeared. AlO2− is transformed into Al(OH)3 and filled in the corrosion pits. At 4 and 5 days, Fe3O4 is generated in the outermost layer, and Al(OH)3 is shed from the corrosion pits. The corrosion mechanism of 12Cr1MoV steel in a TCSA solution is proposed based on the experimental results.

Corrosion of Fe3Al-4Cr Alloys at 1000°C in N2-0.1%H2S Gas

2018 ◽  
Vol 765 ◽  
pp. 173-177 ◽  
Author(s):  
Yu Ke Shi ◽  
Dong Bok Lee
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Xrd Analysis ◽  
Al Alloys ◽  
Corrosion Products ◽  
Al Alloy ◽  
Oxide Scales ◽  
Mixed Gas ◽  
Corrosion Rates

Pure Fe3Al and Fe3Al+4%Cr alloys were corroded at 1000 °C for up to 200 h in N2-0.1%H2S-mixed gas in order to study their corrosion behavior in H2S-containing atmosphere. The formed scales consisted primarily of α-Al2O3, FeAl2O4, and Fe2O3. In these oxide scales, hydrogen and sulfur dissolved according to the reaction; H2S→2H+S. Corrosion products of Cr were not identified in the scales from the XRD analysis, indicating that Cr dissolved in the oxide scales. Fe3Al+4%Cr alloy displayed poorer corrosion resistance than Fe3Al alloy, indicating that chromium accelerated the corrosion rates of Fe3Al alloys.

Elevated electrochemical corrosion behavior of a B4C/Al neutron absorber by shot peening modification

2017 ◽  
Vol 24 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Linlin Zhang ◽  
Wenxian Wang ◽  
Baocheng Wang ◽  
Peng Zhang ◽  
Hongsheng Chen
Keyword(s):  
Corrosion Behavior ◽  
Shot Peening ◽  
High Speed ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Hardness Test ◽  
Corrosion Current ◽  
Al Alloy ◽  
Neutron Absorber ◽  
Modified Layer

AbstractThe shot peening (SP) method was employed to modify the surface properties of 33% B4C/Al composites. The microhardness, morphology, and corrosion behavior of B4C/Al composites were characterized by using the Vickers hardness test, scanning electron microscopy, potential dynamic scanning, and electrochemical impedance spectroscopy. The experimental observations revealed that the B4C particles were embedded into the matrix, which rendered the plastic deformation of Al alloy near the surface of B4C/Al composites on the condition of the high-speed impact of projectiles. As such, the density and hardness of the B4C/Al composite modified layer near the surface were enhanced. After the SP treatment, the results of the electrochemical polarization curve test showed that the corrosion potential increased by 55.2 mV, the corrosion current changed from 3.828×10-6 to 1.102×10-6 A/cm2, and the corrosion rate decreased by 72.2%, respectively. This indicates that the corrosion resistance significantly improved via the SP treatment. The mechanism of the formation of Al alloy modified layer and electrochemical corrosion behaviors is discussed in detail.

Influence of Alloying Elements on Interfacial Reaction and Strength of Aluminum/Steel Dissimilar Joints for Light Weight Car Body

2007 ◽  
Vol 539-543 ◽  
pp. 3888-3893 ◽  
Author(s):  
Akio Hirose ◽  
Hirotaka Imaeda ◽  
Miki Kondo ◽  
Kojiro F. Kobayashi
Keyword(s):  
Interfacial Reaction ◽  
Reaction Layer ◽  
Joint Strength ◽  
Al Alloys ◽  
Interfacial Region ◽  
Chemical Compositions ◽  
Al Alloy ◽  
Dissimilar Joints ◽  
Bonding Parameters ◽  
Bonded Interface

Dissimilar joining of Al alloys and steel was carried out using diffusion bonding process. The effects of Si and Mg contents of Al alloys and bonding parameters on the interfacial reaction were fundamentally investigated. While the reaction layers consisting of Fe-Al type intermetallic compounds (IMCs) formed at the interfacial region, in the joint with Al alloys including 1mass% Si or more a ternary Fe-Al-Si IMC layer formed at the Al alloy side. The growth of the reaction layers followed the parabolic growth low. A maximum joint strength was obtained at an average reaction layer thickness ranging from 0.5 to 1μm. The thicker reaction layer caused the fracture of the joints at a lower stress because of brittleness of the IMCs, and the thinner reaction layer including un-bonded interface also resulted in a low joint strength. As a result a thin and uniform reaction layer including less un-bonded interface can realize a high joint strength. Since the Fe-Al-Si IMC layer uniformly formed more rapidly than the binary Fe-Al IMCs in the joint with Al alloys including 1mass% Si or more, a higher joint strength was obtained at a thinner average reaction layer. As a result, it was found that the chemical compositions of 6000 series Al alloy controlled to be Mg (0.6 to 1.0mass%) and Si (more than 1.0mass%) were appropriate to obtain the better bonding characteristics.

scholarly journals Manufacturing of Ti-6%Al and Ti-6%Al-4%V Alloys and Their Corrosion in Sodium Chloride Solutions

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 181 ◽  
Author(s):  
Hany S. Abdo ◽  
El-Sayed M. Sherif ◽  
Hamed A. El-Serehy
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Al Alloy ◽  
Spectroscopic Techniques ◽  
Uniform Corrosion ◽  
X Ray Diffraction ◽  
Current Time ◽  
X Ray ◽  
Sodium Chloride Solutions

The current research aims at the manufacturing of Ti-6%Al alloy and Ti-6%Al-4%V alloy using the mechanical alloying method and studying their corrosion behavior after various periods of immersions in 3.5% NaCl solutions. The fabricated alloys were also evaluated using spectroscopic techniques such as X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy analyses. The corrosion behavior was studied using potentiodynamic polarization, electrochemical impedance spectroscopy, and chronoamperometric current-time electrochemical methods. It is confirmed that the presence of 4% V greatly decreases the uniform corrosion of the Ti-6%Al alloy as a result of the role of V in decreasing the cathodic, anodic, and corrosion current, and the rate of corrosion along with increasing the corrosion resistance. Increasing the time of immersion to 24 h and further to 48 h highly decreased the corrosion of the alloys. The presence of 4% V and extending the time of exposure thus increase the resistance against corrosion via decreasing the corrosion of Ti-6%Al alloy in the chloride test solution.

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