%0 Journal Article
%T The Effect of Applied Stress on Environment-Induced Cracking of Aluminum Alloy 5052-H3 in 0.5£¿M NaCl Solution
%A Osama M. Alyousif
%A Rokuro Nishimura
%J International Journal of Corrosion
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/894875
%X The environment-induced cracking (EIC) of aluminum alloy 5052-H3 was investigated as a function of applied stress and orientation (Longitudinal rolling direction¡ªTransverse: LT and Transverse¡ªLongitudinal rolling direction: TL) in 0.5£¿M sodium chloride solution (NaCl) using a constant load method. The applied stress dependence of the three parameters (time to failure; , steady-state elongation rate, , and transition time at which a linear increase in elongation starts to deviate, ) obtained from the corrosion elongation curve showed that these relationships were divided into three regions, the stress-dominated region, the EIC- dominated region, and the corrosion-dominated region. Aluminum alloy 5052-H3 with both orientations showed the same EIC behavior. The value of / in the EIC-dominated region was almost constant with independent of applied stress and orientation. The fracture mode was transgranular for 5052-H3 with both orientations in the EIC-dominated region. The relationships between log and log for 5052-H3 in the EIC-dominated region became a good straight line with a slope of £¿2 independent of orientation. 1. Introduction The environment-induced cracking (EIC) behavior of metallic alloys in chloride and other corrosive solutions has been extensively investigated using various EIC methods [1¨C7], where EIC is composed of stress corrosion cracking (SCC) subjected to anodic reactions such as film formation and dissolution and hydrogen embrittlement (HE) to cathodic reactions such as hydrogen evolution. A number of theories have been developed for cracking mechanisms of aluminum alloys in chloride environments [5¨C9]. Suresh et al. have concluded that EIC behavior in high-strength 7075 aluminum alloy under fatigue loading is mostly governed by three mechanisms, namely, the embrittling effect by the hydrogen products of the electrochemical reactions at the crack tip, the role of microstructure and slip mode and crack closure arising from environmental and microstructural elements [8, 9]. It has been reported that the behavior of the metallic alloy can be characterized using a constant load method [10]. The method can produce a corrosion elongation curve which can be used to obtain three parameters, namely, time to failure ( ), steady-state elongation rate ( ), and transition time at which a linear increase in elongation starts to deviate ( ). These parameters were confirmed to be used in analyzing the failure behavior and to predict time to failure ( ) [11, 12]. The objectives of this research work are (1) to investigate the effect of applied stress
%U http://www.hindawi.com/journals/ijc/2012/894875/