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Time and Temperature Dependent Damage Characteristics of 5083 Al Alloy under Cavitation-Corrosion Condition

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Lee S., Han M., Jeong J., Kim M., Kim S.

Acta Physica Polonica A

2016

vol. 129

issue 4

747-752

Continuous efforts to construct high-speed and lightweight ship have been made to reduce cost against growing oil prices. In this context, aluminum has received attention as an alternative material for steel, for small and medium-sized ships. In an effort to extend service life of aluminum, various researches have been attempting to improve the corrosion resistance and anti-corrosion characteristics by applying heat treatment and alloying. The material, however, has a high probability of being attacked by corrosion and erosion, caused by high ship speed in severe marine environments. Cavitation damage is dependent on several important factors, such as shape of objects, surface roughness, rotation speed, fluid pressure and velocity. Vapor pressure, density and surface tension of fluid are also taken into account. In this study, an electrochemical cavitation erosion-corrosion experiment was conducted as a function of solution temperature and applied amplitude for 5083-O aluminum alloy used commercially as a hull material for a small sized ship. The result of the experiment revealed that the damage was accelerated due to synergistic effect of corrosion and erosion as the solution temperature was elevated, and that the weight loss showed a steady increase with increasing time of cavitation.

Photoluminescence Studies of Aluminum Nitride Nanowires

73%

Yang J., Na H., Kim H., Kebede M., Choi R., Jeong J., Lee C., Kim H.

Acta Physica Polonica A

2011

vol. 119

issue 2

125-127

We report the production of AlN nanowires by the thermal heating method, for exploring their photoluminescence properties. The room-temperature photoluminescence properties were investigated with different annealing environment. While broad emissions with peaks at around 2.45 and 2.95 eV were obtained from both unannealed and annealed samples, the additional 2.1 eV peak was found from the annealed samples. We have suggested the possible emission mechanisms based on the assumption that both 2.45 eV peak and 2.1 eV peak are ascribed to the nitrogen vacancies. Annealing in N_2 environment exhibited lower intensities of 2.45 eV peak and 2.1 eV peak in comparison to those in Ar environment, presumably due to the suppression of nitrogen vacancies.

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2 Acta Physica Polonica A

1 2016

1 2011

2 Jeong J.

1 Choi R.

1 Han M.

1 Kebede M.

1 Kim H.

1 Kim M.

1 Kim S.

1 Lee C.

1 Lee S.

1 Na H.

1 Yang J.

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Time and Temperature Dependent Damage Characteristics of 5083 Al Alloy under Cavitation-Corrosion Condition

Photoluminescence Studies of Aluminum Nitride Nanowires