The Resistance of Wrought High Strength Aluminum Alloys to Stress Corrosion Cracking

Abstract

An up to date review of the stress corrosion cracking performance of wrought high strength aluminum alloys is presented. Special emphasis is placed on factors of microstructure and its directionality and the effect of ancillary alloying elements, and environmental factors. Examples of typical service problems encountered with stress corrosion cracking of high strength aluminum alloys are described along with means of combating them, such as peening, coatings, or the use of special stress corrosion resistant alloys.

Stress corrosion theory of crack propagation with applications to geophysics

“…Many of the cracks in rocks are intergranular, rather than transgranular, so that the experimental data for slow cracking in glass and single crystals may have little application to understanding the behavior of cracks in the immediate vicinity of grain boundaries between phases of different composition. Stress corrosion in many materials, however, is intergranular [Brown et al, 1972], and therefore the suggested mode of slow cracking in rocks may be correct. The effect of grain size on cracks is uncertain, so the research results on fine-grained ceramics may not be applicable to rocks with coarser grain sizes.…”

“…According to the definition used in the present paper, stress corrosion cracking may be distinguished from other forms of slow crack growth and from phenomena that are due to corrosion alone [Brown et al, 1972;Speidel, 1971a]. The definition excludes types of purely mechanical failure (independent of environment) such as fatigue (due to intermittent loading) and crack growth due to creep in the absence of corrosion.…”

Predictive Modeling of Corrosion in Al/Mg Dissimilar Joint

“…A and B are potentially able to form more symmetrical and/or packed structures if they have relatively small and similar atomic radii [18]. Having similar atomic radii, electronegativity, crystal structure, and heat capacity, alloys of aluminum and magnesium (e.g., Al 5000, 6000, and 7000 series) are highly resistant to different types of corrosion [19][20][21]. In Figure 1A, it is schematically illustrated that if chemical composition changes in a direction perpendicular to the dissimilar joint (y direction), the gradient of the force perpendicular to the plane of the dissimilar joint is maximum with respect to the y direction (…”

Notch Corrosion Fatigue Behavior of Ti-6Al-4V

“…Data for smooth and notched (with low stress concentration factors) Ti-6Al-4V samples, fatigue tested in laboratory air or aggressive environment, are available in the literature [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ], while only in a few references can the results at high stress concentration factors and in a very aggressive environment be found [ 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”

“…However, the influence of a mechanical action or abrasive can remove this surface layer, generating a direct interaction between the Titanium alloy and the external environment, leading to the appearance of relevant phenomena of stress corrosion cracking in an aqueous environment [ 17 ]. This interaction is also generated by the presence of surface discontinuities, such as cracks, damage and notches, which break the continuity of the passivating layer of oxide, generating in this case also the susceptibility to stress corrosion cracking in water [ 13 , 14 ].…”