جستجوی مقالات مرتبط با کلیدواژه « T6 aluminum alloy » در نشریات گروه « فنی و مهندسی »

Aluminum alloys due to high strength to weight ratio and good corrosion resistance as compared with other metals, have many applications in sea industries. Most of sea structures are under cycle loadings and these leads to fatigue process. Also, because the structures are in a corrosive environment, sea water, so corrosion process effects on them too and leads to destroy efficiency of the this structures. So investigation of effect of fatigue and corrosion together are an important factor in selecting of an aluminum alloys. In this paper corrosion fatigue behavior of 7075-T6 aluminum alloy was investigated and with obtained results from fatigue test in air was compared. results of the paper shows that a corrosive environment had detrimental effects on the specimen was under cyclic loadings and led to decrease corrosion fatigue life of this alloy in a corrosive environment such as sea water. Corrosive environment lead to form pits on specimens surface and fatigue crack can initiate from the pits and propagate. Fatigue strength of the alloy 33% decreased as compared with specimen in air.

In this research, mechanism of HF effect and fluoride ions on corrosion behavior of aluminum alloy 6061-T6 in 30% nitric acid by used Electrochemical tests have been investigated by electrochemical test. Cyclic polarization and impedance electrochemical tests results showed that with increasing concentration of HF, pitting potential decreased and sensivity to pitting increased. SEM image showed that alloy surface been intensely corroded by formation of pits.The mechanism of localized corrosion have been determined by EDS-SEM. The results showed that Fluoride ions with creating fluoride layers on aluminum alloy 5000 series fortified corrosion resistance but formation of H2SiF6 acid that has intenstified the pitting corrosion of the 6061-T6 alloy surface.

In this research, corrosion inhibition of 6061-T6 aluminum alloy in nitric acid by inhibitor of thiourea in two type of solution using tests electrochemical and quantum mechanical calculations have been investigated. Cyclic polarization and electrochemical impedance results showed that with increasing concentrations of inhibitors, pitting potential rosed and sensitivity to pitting diminishes. Anodic and cathodic polarization curves showed that the inhibition was mixed type inhibitors and the inhibition efficiency increases with increasing inhibitor concentration. Inhibitor adsorption on the surface from the Langmuir isotherm can follow. Adsorption free energy calculations revealed that corrosion inhibition is type of physical adsorption. Quantum chemical calculations showed that the inhibitor adsorption on the alloy surface through nitrogen and sulfur atoms as well as π electrons done and reduces the energy difference between the HOMO and LUMO significant role has increasing inhibition efficiency.