Corrosion of 2024 alloy after ultrasonic impact cladding with iron

Abstract

The iron-containing layers were produced on the 2024 alloy surface using ultrasonic impact treatment (UIT) in the ambient air and argon environment. Multiple high-energy collisions of the pin of Armco-iron by the treated surface induce the iron cladding by means of solid-state welding of Fe dopants and Al substrate. SEM and EDX analysis and microhardness measurements showed a formation of oxide/intermetallic layers, which thickness ranges from 15–20 to 30–35 μm and hardness achieves ∼4 and ∼9 GPa after the argon-UIT and air-UIT processes, respectively. The polarisation tests in 3.5%NaCl medium showed that the layers are characterised by lower corrosion rates and more positive corrosion potentials than those of the original alloy owing to the formation of Al x -Fe y intermetallics. The noblest behaviour was registered for the air-UIT-processed 2024 alloy.