scholarly journals Corrosion Behavior of 7075 and 2A12 Aluminum Alloys in Different Water Environments

2021 ◽  
Vol 2101 (1) ◽  
pp. 012082
Author(s):  
Zhipeng Wu ◽  
Shan Wang ◽  
Nan Zhen

Abstract The corrosion of 7075 and 2A12 aluminium alloys are studied in three types of water, including freshwater lake water, salt lake water and saline lake brine in the Qinghai-Tibet Plateau region. The samples are immersed into the different water for different time, which are divided into four types of 30d, 60d, 90d and 120d. After undergoing dry and wet cycle immersion corrosion under natural conditions, it can be concluded that the two aluminum alloy samples have more serious corrosion in freshwater lakes, and 2A12 aluminum alloy is more corrosion resistant than the 7075 aluminum alloy. The corrosion is mainly pitting, accompanied by crevice corrosion and galvanic corrosion. Cl − can pass through the passivation film on the surface of the samples to form pitting pits, while the dissolved Al 3+ in the matrix and S O 4 2 − in the water can form stable Al 2(SO 4)3 ▪ xH 2 O, which plays a certain protective role for the sample.

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Huiling Zhou ◽  
Fanglian Fu ◽  
Zhixin Dai ◽  
Yanxin Qiao ◽  
Jian Chen ◽  
...  

The 6061-T6 aluminum alloy welding joints were fabricated using gas metal arc welding (GMAW) of various laser powers, and the effect of laser power on the microstructure evolution of the welding joints was investigated. The corrosion behaviors of 6061-T6 aluminum alloy welding joints were investigated in 3.5 wt% NaCl solution using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the micro-galvanic corrosion initiation from Mg2Si or around the intermetallic particles (Al-Fe-Si) is observed after the immersion test due to the inhomogeneous nature of the microstructure. The preferential dissolution of the Mg2Si and Al-Fe-Si is believed to be the possible cause of pitting corrosion. When the laser power reached 5 kW, the microstructure of the welded joint mainly consisted of Al-Fe-Si rather than the Mg2Si at 2 kW. The relatively higher content of Al-Fe-Si with increasing in laser power would increase the volume of corrosion pits.


This article explores narrative organisation of the event in the literary story Nunc dimittis by T. Lee and the screen version of the same name. The event in its entirety of concrete episodes is a change of states with the known and the unknown confronting each other throughout the whole narrative. The character of the known side is a young criminal, while a female vampire and her servant stand for the unknown. The literary story and its screen version (the filmic narrative) are brought to comparison in terms of the authentic retranslation that reproduces the original event in another (cinematic) medium in detail, but with minor fluctuations seen in each episode separately. In the article, the mode of retranslation is shown according to the pattern the original – a transponent, where the original is the initial, primary work, and transponents are the products of intermedial, or extracompositional reinterpretation (in this article the only existing screen version is at issue). All adaptations, notwithstanding their number, make up the matrix of a certain narrative together with the original. The literary as well as the filmic episodes of Nunc dimittis resolve into three types of mise en scène where the latter term is defined as the elements that make up the event. The types suggested include the enclosed mise en scène keeping all the participants inside up to its end; the pass-through mise en scène that adheres to one of the characters who is in and out; the open mise en scène where the characters take turns in coming and going. Minor differences between the original and its transponent concern the symbolic load on the names of characters and their actions, which do not change, but rather amplify the original message of the story.


2018 ◽  
Vol 18 (18) ◽  
pp. 18-23 ◽  
Author(s):  
Sandra Veličković ◽  
Slavica Miladinović ◽  
Blaža Stojanović ◽  
Ružica R. Nikolić ◽  
Branislav Hadzima ◽  
...  

Abstract Hybrid materials with the metal matrix are important engineering materials due to their outstanding mechanical and tribological properties. Here are presented selected tribological properties of the hybrid composites with the matrix made of aluminum alloy and reinforced by the silicon carbide and graphite particles. The tribological characteristics of such materials are superior to characteristics of the matrix – the aluminum alloy, as well as to characteristics of the classical metal-matrix composites with a single reinforcing material. Those characteristics depend on the volume fractions of the reinforcing components, sizes of the reinforcing particles, as well as on the fabrication process of the hybrid composites. The considered tribological characteristics are the friction coefficient and the wear rate as functions of the load levels and the volume fractions of the graphite and the SiC particles. The wear rate increases with increase of the load and the Gr particles content and with reduction of the SiC particles content. The friction coefficient increases with the load, as well as with the SiC particles content increase.


2012 ◽  
Vol 29 (6) ◽  
pp. 818-822 ◽  
Author(s):  
Ahmed Y. Musa ◽  
Abu Bakar Mohamad ◽  
Ahmed A. Al-Amiery ◽  
Lim Tien Tien

2019 ◽  
Vol 130 ◽  
pp. 01005
Author(s):  
Cindy Retno Putri ◽  
Anne Zulfia Syahrial ◽  
Salahuddin Yunus ◽  
Budi Wahyu Utomo

The goal of this research is to improve the mechanical properties such as strength, hardness and wear resistance for automotive application such as brake shoe and bearings due to high cycle, load and impact during their usage. Therefore, another alloying element or reinforcement addition is necessary. In this work, the composites are made by ADC 12 (Al-Si aluminum alloy) as the matrix and reinforced with micro SiC through stir casting process and TiB is added various from (0.04, 0.06, 0.15, 0.3 and 0.5) wt.% that act as grain refiners and 5 wt.% of Mg is added to improve the wettability of the composites. The addition of TiB improves the mechanical properties because the grain becomes finer and uniform, and the addition of Mg makes the matrix and reinforce have better adhesion. The results obtained that the optimum composition was found by adding 0.15 wt.% of TiB with tensile strength improve from 98 MPa to 136.3 MPa, hardness from 35 to 53 HRB and wear rate reduced from 0.006 2 mm3 s−1 to 0.002 3 mm3 s−1 respectively.


2017 ◽  
Vol 26 (12) ◽  
pp. 6099-6106 ◽  
Author(s):  
Yuanhang Yang ◽  
Yanhong Gu ◽  
Lei Zhang ◽  
Xiangdong Jiao ◽  
Juntie Che

2013 ◽  
Vol 550 ◽  
pp. 127-134
Author(s):  
Nicoleta Radutoiu ◽  
Joël Alexis ◽  
Loïc Lacroix ◽  
Marioara Abrudeanu ◽  
Jacques Alain Petit

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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