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Most supersonic aircraft were manufactured using 2A70 aluminum alloy. The purpose of this paper is to study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue.

For this purpose, the aluminum alloy samples were subjected to pre-corrosion and alternating corrosion-fatigue experiments. The failure mechanisms of corrosion and corrosion fatigue were analyzed using microscopic characterization methods of electrochemical testing, X-ray diffraction and scanning electron microscopy. Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life.

The results showed that the corrosion damage caused by the corrosive environment was gradually connected by pitting pits to form denudation pits along grain boundaries. The deep excavation of chloride ions and the presence of intergranular copper-rich phases result in severe intergranular corrosion morphology. During cyclic loading, alternating hardening and softening occurred. The stress concentration caused by surface pitting pits and denudation pits initiated fatigue cracks at intergranular corrosion products. At the same time, the initiation of multiple fatigue crack sources was caused by the corrosion environment and the morphology of the transient fracture zone was also changed, but the crack propagation rate was not basically affected. The polarization curve and impedance analysis results showed that the corrosion rate increases first, decreases and then increases. Fatigue failure behavior was directly related to micro characteristics such as corrosion pits and microcracks.

In this research, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue. To study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, the Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life.

In summary, it can be found that the current research on the simulation of natural atmospheric dry–wet alternating accelerated corrosion mainly focused on the study of electrochemical corrosion process and the study of corrosion rate; the micro-pre-corrosion mechanism of materials in this environment, especially for materials. The specific effects of fatigue and fracture performance still lack detailed research. Accordingly, this study aims to more realistically simulate the effect of natural atmospheric corrosion environment on the corrosion resistance and fatigue performance of aircraft skin.

In this study, the uniaxial strain control method was used to test the fatigue performance of pre-corrosion samples under simulated natural atmospheric corrosion using MTS809 tensile-torque composite fatigue machine. Scanning electron microscopy, X-ray energy spectrum analysis, atomic force microscopy and X-ray diffraction analysis were used. Fatigue fracture, corrosion morphology and corrosion products were analyzed.

The results show that the deep corrosion pit caused by pre-corrosion environment leads to multi-source initiation of crack; the fatigue life of pre-corroded sample decreases by about one-half, chloride ion invades the material and promotes intergranular corrosion; life prediction results show that the natural atmospheric corrosive environment mainly affects the plastic term in the Manson–Coffin formula resulting in a decrease in fatigue life.

Innovative experimental schemes and materials are used and the test temperature and relative humidity are strictly controlled. The corrosion failure mechanism of 2A70-T6 aluminum alloy under alternating wet and dry accelerated corrosion environment and its influence on fatigue behavior were obtained.

Work has been performed to assess the corrosion inhibiting performance of a tertiary amine possessing two carboxylic acid groups (N coco‐amine‐2‐proprionic acid), on initially clean and pre‐corroded mild steel. Using linear polarisation and AC impedance high levels of efficiency were measured within the first hour of inhibitor addition at a concentration level of 10ppm. Simultaneously rapid anodic changes in corrosion potential were observed. With increasing pre‐corrosion decreased efficiencies were obtained, but still greater than 90 per cent, and this coincided with a less rapid alteration in steady state potential. The good response of the inhibitor has been attributed to the adsorption of negatively charged oxygens at the anodic sites on the metal surface, although pitting was detected once testing was terminated. Previously using inhibitors possessing positive charges (short and long chained quarternary amines), under the same environmental conditions, efficiencies > 90 per cent after the first hour were not achieved.

This paper aims to introduce a method to reduce corrosion caused by acidic-oxidized polymer degradant through subsection injection with different inhibitor.

This paper introduced a method to reduce corrosion caused by acidic-oxidized polymer degradant through subsection injection with different inhibitor.

The experimental results indicated that the influence of pre-corrosion status on corrosion rate and effectiveness of corrosion inhibitor are significant. The corrosion inhibitors in both injection stage inhibited the corrosion process by preventing the contact of corrosive medium and steel surface through formation of a protective film on the surface of N80 steel. The corrosion rate of polymer degradant can be reduced to 0.63 g/m 2 h through subsection injection with different inhibitor.

This result will increase the production of polymer injection plugging wells through expanding the application of acidic-oxidized polymer degradant.

Work has been performed to investigate the effect of pH on the performance of a tertiary amine possessing a single carboxylic acid group. The efficiency of this inhibitor and speed at which the efficiency increased were able to show a strong pH dependency, indicating that in such systems pH monitoring is important. Measurements have revealed that when the pH was lowered from 6.5 to 3.9 different changes in corrosion potential were observed after inhibitor addition and that the efficiency of the inhibitor decreased with increasing acidity. It is believed that cause (on clean and pre‐corroded specimens) is related to variations in the chemistry of the inhibitor such that at pH 6.5 inhibition is primarily due to O^‐ adsorption at anodic sites, while at pH 3.9 decreased corrosion rates occur as a result of the inhibitor loosely lying flat at the metal solution interface. It is also proposed that between the pH range studied the steel surface consists mainly of anodic sites.

The increasing incidence of corrosion induced failures query the efficiency of corrosion prevention measures and/or their monitoring techniques. Of concern too, is the phenomenon of twelve o'clock corrosion and the subsequent rupture. This indicated that the inhibitor was not protecting the upper surface of the pipe wall which could be possibly averted by batching a slug of inhibitor solution ahead of a pig or between pigs on regular (e.g. monthly) basis.

Work has been performed to investigate the effect of inhibitor charge and pH, in the range 3.9 to 6.5, on the efficiency of various tertiary and quaternary amines. Results have revealed that for such adsorption type inhibitors performance at a given pH depends critically upon the charge of the adsorbing species. At pH 6.5 highest efficiencies were attained when the net charge on the inhibitor was negative, while at pH 3.9 positively charged species were discovered to give better results. Based on the data obtained it is suggested that at pH 6.5 the corrosion potential is more noble than the potential of zero charge causing the metal surface to be predominantly composed of positive charges. At the other end of the spectrum (pH 3.9), the situation is thought to be reversed thus aiding better the adsorption of positively charged inhibitors.

Strategic management dictates that the arrangement for corrosion control and monitoring should be made during project construction. Subsequent modification/ rectification to accommodate such omissions is uneconomical because of the additional outlay incurred. Contractual obligation cannot absorb such a cost. However, changes in corrosion characteristics resulting from, say, alteration in feed stock and/or operating conditions, may make such a rectification mandatory.

The purpose of this paper is to study the effect of surface salt spray duration on the fretting wear and electrochemical corrosion behaviors of Inconel 690 alloy.

A high-temperature steam generator was applied to salt spray test samples, a fretting wear rig was used to realize the damage behavior tests, an electrochemical workstation was applied to analysis the changes of each sample’s corrosion dynamic response before and after fretting wear.

The thickness of the oxide film that formed on sample surface was increased with the salt spray duration, and somewhat it could act as lubrication during the fretting wear process; however, the corrosive chloride would accelerate the fretting mechanical damage behavior.

In a salt steam spray condition, the fretting tribo-corrosion behaviors of Inconel 690 alloy surface was studied.

The purpose of this paper is to examine new alloys created from Alumix 431 powder and investigate their mechanical and electrochemical properties.

In this study; Alumix-431 alloy samples were prepared using the powder metallurgy (P/M) method applying cold (RT) and warm (50°C and 80°C) compaction methods under pressures of 200 and 250 MPa and were sintered at 600°C in N₂(g) atmosphere. Hardness and density of the samples were measured, and corrosion properties were determined by electrochemical impedance spectroscopy charting polarization curves. Surface characterization was determined by contact angle, scanning electron microscopy/mapping, energy dispersive X-ray spectrometry and X-ray diffractometry images.

Alumix-431 alloys obtained upon compaction at 250 MPa/50 °C had the highest mechanical properties and corrosion resistance and good surface properties. On the surfaces of Alumix-431 alloys, α-Al, MgZn₂, Al₂,CuMg, Al₂,O₃, Al₂MgO₄ phases were recorded.

This study aimed to construct a correlation between mechanical and electrochemical properties of the newly created alloys (prepared under special conditions).