scholarly journals Study on the Correlation between the Microstructure Characteristics and Corrosion Behaviors of 2A12-T4 Aluminum Alloy under Thermal Strain

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 924
Author(s):  
Shuaihao Qian ◽  
Timing Zhang ◽  
Yuhua Chen ◽  
Hongxiang Li ◽  
Jilin Xie ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Dynamic Recrystallization ◽  
Grain Boundaries ◽  
Corrosion Behavior ◽  
Tensile Strain ◽  
Thermal Strain ◽  
Peak Temperature ◽  
Microstructure Characteristics ◽  
Precipitated Phase

In this study, the welding thermal simulation technology was used to prepare samples under different peak temperatures and strain levels in order to reveal the effects of thermal strain on the microstructure characteristics and corrosion resistance of aluminum alloy. Furthermore, the correlation between microstructure evolution law and corrosion behavior was studied by analyzing the microstructure characteristics and performing electrochemical polarization curve tests. Results showed that the amount and distribution of the precipitated phase were the main factors affecting the corrosion behavior of aluminum alloy. The precipitated phase was distributed along the direction of tensile strain, and the grain size was coarsened from 152 to 260 μm (and even exceeded 280 μm) after experiencing peak temperatures of 300 and 400 °C. In addition, the risk of corrosion for the samples that experienced thermal strain was increased compared to those that did not undergo tensile strain. The samples that experienced a peak temperature of 300 °C presented the best corrosion resistance as the precipitated phase was evenly distributed in the matrix. However, when the peak temperature was 400 °C and the strain was 8%, the number and density of the precipitated phase increased due to the dynamic recrystallization, and the corrosion resistance of the sample became the worst. Finally, the microstructure analysis results showed that dynamic recrystallization occurred in the sample with a peak temperature of 400 °C, and the precipitated phase was mainly distributed along the grain boundaries. This led to the decrease of the corrosion resistance of grain boundaries, and the corrosion developed from pitting corrosion to intergranular corrosion.

Computational and Experimental Insights into the Role of Acidic Molecules on the Corrosion Behavior on 7A46 Aluminum Alloy

2021 ◽  
Vol 21 (4) ◽  
pp. 2221-2233
Author(s):  
Yaru Liu ◽  
Qinglin Pan ◽  
Xiangdong Wang ◽  
Ye Ji ◽  
Qicheng Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
First Principles ◽  
First Principles Calculations ◽  
Corrosive Media ◽  
Corrosion Depth ◽  
Corrosion Mechanisms ◽  
Nanoscale Level

The corrosion mechanisms for different corrosive media on the aged 7A46 aluminum alloy were systematically investigated at nanoscale level. The combination of empirical intergranular and exfoliation corrosion behavior was employed, and coupled with first-principles calculations. Results revealed that the dispersed distribution of matrix precipitates (MPs) leads to the enhancement of the corrosion resistance pre-ageing (PA) followed by double-ageing (PA-DA) alloy. The deepest corrosion depth of PA-DA alloy was in hydrochloric acid, and the calculation result demonstrates that the passivation effect in combination with the accumulation of corrosion products in nitric acid protect the PA-DA alloy from further corrosion.

Correlation of Surface Alloyed Microstructure of Pure Magnesium With its Corrosion Behavior

2012 ◽  
Vol 472-475 ◽  
pp. 161-164
Author(s):  
Yu Gao Liu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Chloride Solution ◽  
Diffusion Time ◽  
Point Of View ◽  
Pure Magnesium ◽  
Corrosion Mechanism ◽  
Cross Sectional ◽  
Microstructure Characteristics ◽  
Solid Diffusion

This paper represents a summary of experimental results dealing with the time dependence of surface diffusion alloyed microstructure and its corrosion behavior at given temperature. The experiments were performed at 485°C for different solid diffusion time (6h, 12h, 18h ) and thus the surface alloyed microstructure of pure magnesium has been obtained. Optical and electrical microscopy and EDS compositions analysis were used to examine the cross sectional microstructure characteristics of alloyed layers of treated samples. It is shown that the new phases formed and its continuity, depending on the diffusion treated time at given temperature, have a noticeable influence on corrosion resistance and corrosion mechanism. The new formed phase Al5Mg11Zn4 was inert to the chloride solution compared with pure magnesium and acted as a corrosion barrier. It was concluded that the continuous Al5Mg11Zn4 phase was beneficial from the point of view of corrosion resistance.

scholarly journals Corrosion Behavior of a WC/C Coated 7075-T6 Aluminum Alloy

2013 ◽  
Vol 577-578 ◽  
pp. 217-220
Author(s):  
Sergio Baragetti ◽  
M. Daurù ◽  
Riccardo Gerosa ◽  
Barbara Rivolta
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Experimental Tests ◽  
Point Of View ◽  
Surface Finishing ◽  
Polished Surface ◽  
Foreign Object ◽  
Final Thickness

In the present experimental work, a WC/C coated 7075-T6 aluminum alloy was considered from the corrosion point of view. The coating was deposited by PVD technique with a final thickness of about 2.5μm. In order to study the influence of the coating on the corrosion behavior of the aluminum alloy, the samples surfaces were partially coated and the interface among the metal and the coating was analyzed after the corrosion tests described into the ASTM G110 standard. Such experimental plan was decided in order to simulate the possible in-service local removal of the thin and hard coating. This kind of damage, due for example to a foreign object impact, can occur because of the great hardness difference between the coating and the substrate. The experimental tests were carried out on samples with different surface finishing, ranging from about 0.02μm Ra (mirror-polished surface) to about 0.8μm Ra (320 grit paper). The aim of such choice was to investigate the effect of a surface roughness different from the optimal one (mirror polished) on the coating deposition. Moreover a different corrosion resistance is expected.

Microstructure and Corrosion Behavior of Laser Cladding Al3Ti-Based Composite Coatings on AA6063 Aluminum Alloy

2013 ◽  
Vol 634-638 ◽  
pp. 2973-2978 ◽  
Author(s):  
Huan He ◽  
Yue Chun Fu ◽  
Wei Hua Guo ◽  
Min Xiao ◽  
Xing Zhi Pang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Intermetallic Compound ◽  
Uniform Distribution ◽  
Laser Irradiation ◽  
Corrosion Behavior ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Nacl Solution ◽  
Aa6063 Aluminum Alloy

Intermetallic compound Al3Ti-based IMC coatings were formed on AA6063 aluminum alloy by laser cladding. The microstructure and corrosion characteristics in 3.5% NaCl solution were investigated. The results show that, the laser cladding coating is made up of Al3Ti dendrites, interdendritic α-Al and uniform distribution of TiC which hardly melted during laser irradiation, and shows good bonding to the substrate. The cross distribution of Al3Ti and α-Al helps to avoid the generation of cracks in the coating. The corrosion resistance of the laser cladding coatings is greatly increased as compared with the substrate, which owes mainly to the existence of hard Al3Ti and TiC. And with the increasing of TiC content in the coating, the corrosion resistance is improved simultaneously.

Effects of interrupted aging on the intergranular corrosion behavior of Al–Cu–Mg–Ag heat-resistant alloy

2016 ◽  
Vol 13 (6) ◽  
pp. 476-481 ◽  
Author(s):  
Ruijie Zhang ◽  
Xiaoyan Liu ◽  
Zhaopeng Wang ◽  
Fei Gao
Keyword(s):  
Corrosion Resistance ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Corrosion Behavior ◽  
Intergranular Corrosion ◽  
Al Alloy ◽  
Content Type ◽  
Heat Resistant Alloy ◽  
Resistant Alloy ◽  
Heat Resistant

Purpose The purpose of this study is to research the effects of interrupted aging on the corrosion behavior of Al–Cu–Mg–Ag heat-resistant alloy by means of intergranular corrosion (IGC) testing, potentiodynamic polarization combined with optical microscopy and transmission electron microscopy. Design/methodology/approach The results show that the IGC began on the grain boundaries and continued along the grain boundary. The corrosion resistance property of Al–Cu–Mg–Ag alloy was enhanced by interrupted aging. The precipitations of the interrupted aged sample both in the grains and on the grain boundaries were fine, and the chain-like phases on the grain boundary were distributed nearly continuously. Findings The corrosion resistance of Al–Cu–Mg series Al alloy with equilibrium phase (Al2Cu) is notably determined by precipitation-free zone (PFZ) as the self-corrosion potentials of (Al2Cu), PFZ and the matrix satisfied the relation EPFZ < Eθ<EMatrix. Originality/value The connections of the PFZ on both sides of the grain boundary decreased the corrosion resistance of Al–Cu–Mg–Ag alloy treated by the single aging.

scholarly journals Effects of Ultrasonic Surface Rolling on the Localized Corrosion Behavior of 7B50-T7751 Aluminum Alloy

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 738
Author(s):  
Xingchen Xu ◽  
Daoxin Liu ◽  
Xiaohua Zhang ◽  
Chengsong Liu ◽  
Dan Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Compressive Residual Stress ◽  
Rolling Process ◽  
Test Solution ◽  
Localized Corrosion ◽  
Homogeneous Surface ◽  
Passivation Film ◽  
Immersion Testing

The effects of an ultrasonic surface rolling process (USRP) on the localized corrosion behavior of 7B50-T7751 aluminum alloy in a sodium chloride + hydrogen peroxide solution were investigated through microstructural observation, immersion testing, and electrochemical measurements. The results revealed that this alloy is prone to pitting. However, the localized corrosion resistance can be significantly improved via both one-pass USRP and 12-pass USRP treatment. Furthermore, in the test solution, the thickness and the acceptor density of the passivation film were affected by the USRP treatment. The improved corrosion resistance of one-pass USRP-treated samples resulted mainly from the introduced compressive residual stress. However, this stress played a secondary role in the considerable enhancement observed for the corrosion resistance of the 12-pass USRP-treated samples. This enhancement is attributed primarily to the nanocrystalline surface and homogeneous surface microstructure induced by the multiple-pass USRP treatment.

Corrosion Behavior and Microstructure of Pd Ions Doped Cerium Conversion Coating on AA2219-T87 Aluminum Alloy

2015 ◽  
Vol 1090 ◽  
pp. 79-83
Author(s):  
Yan Hong He ◽  
Zhen Duo Cui ◽  
Xian Jin Yang ◽  
Sheng Li Zhu ◽  
Zhao Yang Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Composite Coatings ◽  
Corrosion Current ◽  
Conversion Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Excellent Corrosion Resistance

In this paper, Pd ions doped cerium conversion coating (CeCC/Pd) was deposited on AA2219-T87 aluminum alloy by electroplating. The microstructure and composition of the coating were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). Corrosion behavior of AA2219-T87 aluminum alloy with the coating was investigated in 3.5wt.% NaCl solution at the room temperature. XRD and XPS results indicate the existence of cerium-oxide and palladium-oxide in the CeCC/Pd. Polarization curves show that the CeCC/Pd exhibits excellent corrosion resistance. The corrosion current density of the CeCC/Pd decreases by two orders of magnitude compared with the CeCC. The improvement of corrosion resistance would be attributed to the small grain size, good compactness and adhesive strength of the composite coatings.

Improvements in Strength and Electrical Conductivity in 7B04 Aluminum Alloy Pre-Stretched Thick Plates Via Low-Temperature Retrogression and Re-Ageing Heat Treatments

2007 ◽  
Vol 561-565 ◽  
pp. 139-142 ◽  
Author(s):  
Zhi Hui Li ◽  
Bai Qing Xiong ◽  
Yon Gan Zhang ◽  
Bao Hong Zhu ◽  
Feng Wang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Low Temperature ◽  
Mechanical Strength ◽  
Grain Boundaries ◽  
Aluminum Matrix ◽  
Thick Plates ◽  
Research Results

The effect of RRA treatment with using low retrogression temperatures between 170°C to 190°C on the strength and electrical conductivity (as an indicator of corrosion resistance) of 7B04 aluminum alloy thick plates was investigated. The research results showed that the low-temperature RRA heat treatment provides a means for improving electrical conductivity of the aluminum alloy 7B04 pre-stretched thick plates without sacrificing the mechanical strength. The RRA temper with retrogression at 180°C for 60 min improved electrical conductivity remarkably (reached 21.0MS/m), with only a 3% reduction in strength below T6 temper. Furthermore, TEM observations showed that the microstructure of RRA treated alloy was a very fine distribution of η′ MgZn2 precipitates in the aluminum matrix, similar to T6 condition and η MgZn2 precipitates on grain boundaries distributed similarly to T73 temper.

Influence of single and dual particle reinforcements on the corrosion behavior of aluminum alloy based composites

2016 ◽  
Vol 232 (6) ◽  
pp. 520-532
Author(s):  
Yogesh K Singla ◽  
Rahul Chhibber ◽  
Avdesh ◽  
Shweta Goyal ◽  
Vipin Sharma
Keyword(s):  
Silicon Carbide ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Single Particle ◽  
Base Alloy ◽  
Corrosion Mechanism ◽  
Reinforced Composites ◽  
Particle Reinforced Composites ◽  
Zircon Sand

This article presents the results of a study on the corrosion characteristics of the single and dual particle reinforced aluminum alloy 6063 based composites. The reinforcements of silicon carbide and zircon sand were utilized to fabricate the composites by stir casting technique. The influence of reinforcement and their weight percentage on the hardness variations was investigated. The electrochemical tests in sodium chloride solution were conducted to study the corrosion performance of reinforced composites and base alloy. From the corrosion analysis, it was observed that the single particle reinforcement offered better solution on enhancing the corrosion resistance of base aluminum alloy in comparison with dual particle reinforced composites. In the single particle reinforced composites, addition of zircon sand exhibited increased corrosion resistance, when compared to silicon carbide reinforced composites. The governing mechanism behind increased corrosion resistance was found to be the absence of galvanic coupling between the elemental compounds and the corrosive media at particle–matrix interface. The scanning electron microscopy of composites was performed to analyze corrosion mechanism and correlated well with the corrosion behavior.

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.

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