High Strength Al-Alloys: Microstructure, Corrosion and Principles of Protection

Electrochemical profiling of multi-clad aluminium sheets used in automotive heat exchangers

“…Aluminium is used extensively in the automotive industry for heat exchangers in radiators, air conditioner evaporators, exhaust gas recirculation (EGR) and water and air charge air cooling (W & A CAC) systems [7]. This is due to its favourable combination of mechanical, thermal, and electrochemical properties [8,9]. Over the last two decades, mechanical assembly in the production of heat exchangers has been continuously replaced by brazing due to its reduced manufacturing costs and compliance with the increased safety requirements and issues related to recyclability [10][11][12].…”

60 Years’ marine corrosion of aluminium alloy 24S (2024) from an historic aircraft wreck site: implications for conservation

“…As resumed in the A.E. Hugues' review, the corrosion behaviour of structural aluminium alloys is mainly dependent on the presence and composition of intermetallic particles [34]. In NaCl medium, the corrosion behaviour of the three bulk intermetallic phases, Al 2 Cu, Al 2 CuMg and Al 7 Cu 2 Fe, reveal that the three phases undergo a dealloying process, leading to the formation of layer of copper nanoparticles that can be also named nanosponge of copper.…”

“…According to potentiostatic measurement on pure phases, the open-circuit potential of Al 2 Cu at −0.64 V and Al 7 Cu 2 Fe at −0.75 V is anodic compared to the OCP of pure aluminium around −0.8 to −0.85 V in NaCl [34,36]. Consequently, in contact with these anodic phases, the aluminium matrix neighbouring the intermetallic particles is oxidised and dissolved in NaCl medium, which can break off the metallic particles from the alloy [36].…”

“…Concerning the behaviour of the Al 2 CuMg phase (OCP = −0.95 V), this cathodic phase is simply oxidised in contact with aluminium matrix to form a copper nanosponge, according to the corrosion behaviour of the pure phase [34][35][36][37].…”

Improvement of Pitting-Corrosion Resistance of Ultrafine-Grained 7475 Al Alloy by Aging

“…SPD methods also lead to fragmentation and a more uniform distribution of intermetallic particles in Al alloys with heterogeneous microstructures [ 20 , 21 , 22 ]. The galvanic coupling of intermetallic particles with the surrounding matrix leads to the initiation of pitting [ 23 , 24 ]. The fragmentation of intermetallic particles is often related to the improvement of corrosion resistance of Al alloys due to the formation of a more continuous passive film and reduction in micro-galvanic currents [ 25 , 26 , 27 , 28 ].…”