Research on the adsorption behavior and corrosion resistance mechanism of Cl ions in aluminum-lithium alloys by pre-deformation

This paper investigates the changes in corrosion resistance of Al-Li alloys under pre-tensile behavior, and discusses the electron transfer and stress–strain of precipitated phases under deformation behavior in Al-Li alloys. First-principles calculations reveal that Cl is more easily adsorbed on Al atoms in Al₃Zr with an adsorption energy of −7.28961 eV. The structure of Cl adsorbed on the Al matrix at the Al (111)/Al₃Li (111) interface is the most stable, with an adsorption energy of −2.54351 eV. Under 1 %-5% strain, the electron cloud distribution at the interface does not change significantly. XRD characterization shows that the precipitation of Al₃Li and Al₃Zr phases is enhanced and the degree of grain refinement is increased under 2 % strain. Tensile and electrochemical experiments indicate that the corrosion rate of the sample under 2 % strain is the lowest (1.0374 mm/a), and the angle value in the low-frequency region changes from 10.623° to 19.57° under 2 % strain, with the largest variation degree, exhibiting the best corrosion resistance. SEM observation of the corrosion morphology shows that the corrosion evolves into intergranular corrosion, and during the corrosion process, intergranular corrosion develops into pitting corrosion, with a large amount of Cl ions adhering to the corrosion pits, leading to spalling of the material surface. This study characterizes the differences in corrosion resistance of Al-Li alloys under different strains, and the research results provide technical guidance for the development of new aluminum alloy materials with high corrosion resistance, light weight, and low cost.