Quantification of Sensitization in AA5083-H131 via Imaging Ga-Embrittled Fracture Surfaces

Abstract

Sensitization of 5xxx series Al alloys involving precipitation of β phase (Mg2Al3) at grain boundaries was studied for different exposure times at 100°C upon AA5083-H131 (UNS A95083). In this work, we reveal that fracture surfaces prepared by liquid gallium embrittlement can yield a quantification of grain boundary β phase with significant statistics on β phase size and spacing. This information is a necessary first step toward development of quantitative damage models to describe inter-granular corrosion (IGC) and stress corrosion (IGSCC).

A microscopic study on the corrosion fatigue of ultra-fine grained and conventional Al–Mg alloy

“…The alloys in this study have enough magnesium to contribute to super saturation of the element and leads to solid solution strengthening at temperatures below $200°C. However, this concentration also yields an abundance of the b-phase (Mg 2 Al 3 ) which is known to be deleterious to the corrosion performance [45][46][47][48]. The formation of the b-phase is associated with susceptibility to intergranular corrosion (IGC), localized corrosion, stress corrosion cracking (SCC) as well as corrosion fatigue (CF); with the worst case scenarios if the phase is located at the grain boundaries [49][50][51][52].…”

Corrosion behaviour and hardness of in situ consolidated nanostructured Al and Al–Cr alloys produced via high-energy ball milling

“…Moreover, high temperature exposure of such alloys causes the formation of intermetallics, which are known to cause severe localised corrosion [14,15]. However, recent studies have shown that the level of corrosion damage depends upon size, distribution, and electrochemical characteristics of the intermetallics [3,7,[14][15][16][17][18]. Intermetallics with similar corrosion potentials as Al, or those unable to sustain large currents at the mixed potential of the alloy minimise localised corrosion.…”

Influence of Mg Content on the Sensitization and Corrosion of Al-xMg(-Mn) Alloys

“…18 Of the various attempts made to understand the effect of β phase on DoS, it is generally believed that DoS increases with an increase in β-phase fraction; however, it is not only the fraction of β phase but also likely its morphology and distribution that plays an important role in determining DoS. 19 Precipi-tation of β phase and its morphology, distribution, and fraction depend on many factors, including processing and alloy composition. Temperature and mechanical deformation have been reported to play a major role in precipitation of β phase.…”