A comparison of AA2024 and AA7150 subjected to ultrasonic shot peening: Microstructure, surface segregation and corrosion

Effects of Ultrasonic Surface Rolling on the Localized Corrosion Behavior of 7B50-T7751 Aluminum Alloy

“…This was attributed to the surface microstructure homogenization caused by the 12-pass USRP treatment, which reduced the surface electrochemical heterogeneity of the sample. This is consistent with the findings of Sun et al [6], who reported that the corrosion resistance of ultrasonic shot-peened AA2024 can be improved by obtaining a surface layer with a homogeneous microstructure.…”

“…However, corrosive media with high concentrations of chloride ions lead to rupture of the passive film and, consequently, both uniform and localized corrosion [5]. Compared with uniform corrosion, localized corrosion (for example, pitting corrosion, intergranular corrosion (IGC), and crevice corrosion) is more common and detrimental to aluminum alloy components [6]. Therefore, the corrosion prevention is essential and is ordinarily achieved via diverse types of coatings [3,[7][8][9][10] or under conditions where mechanical and microstructural improvements are required, with different surface treatment technologies [11][12][13].…”

Improving Corrosion and Corrosion-Fatigue Resistance of AZ31B Cast Mg Alloy Using Combined Cold Spray and Top Coatings

“…The presence of intermetallics also influences the electrochemical reaction of the materials by forming local cell action at the grain boundaries. The formation of the local cells depends on the potential of the matrix and the intermetallics [71,72]. The intermetallic MgZn 2 present in coating material AA7075 is less noble than the Al-matrix.…”

“…They will be acted as anodes and the Al-matrix acted as cathode in NaCl solution. Sun et al [71] reported that shot peening can dissolve the nano-precipitates like MgZn 2 into Al matrix, which form a homogeneous microstructure that reduces the vulnerability of corrosion. As seen in Figure 4, the intermetallics of MgZn 2 was identified which form local cells in the coating leading to the formation of pits (Figure 8c).…”

“…As seen in Figure 4, the intermetallics of MgZn 2 was identified which form local cells in the coating leading to the formation of pits (Figure 8c). Reboul et al [73] and Sun et al [71] reported that to avoid the pits repassivation, a critical Cl − and H + concentration is required to obtain the propagating pits stabilizations. When the localized cells are formed, a concentrated AlCl 3 solution having pH of 3 is produced in the pits.…”