Age-hardening behavior, corrosion mechanisms, and passive film structure of nanocrystalline Al-V supersaturated solid solution. (1st February 2023) - Christudasjustus, J.
Highlights: Synthesis of a nanocrystalline Al-5at.%V alloy with high solid solubility of V by high-energy ball milling Study on the age hardening behavior of the ball milled Al-V alloy Corrosion behavior as a function of age hardening time and temperature Study of the passive film and pits using transmission electron microscope Microstructural features causing passive film breakdown and subsequent pit growth or repassivation Abstract: The effect of age-hardening on microstructure, hardness, and corrosion of an Al-5at.%V alloy, produced using high-energy ball milling and subsequent cold compaction, has been investigated. The alloy exhibited a grain size below 100 nm and extremely high solid solubility of V in Al (3.1 at.%). The age-hardening was carried out at 150, 200, and 250 °C. The peak-aged condition of 150 °C demonstrated the highest hardness—transpired from grain refinement, precipitation, and solid solution hardening. The corrosion resistance of the Al-5at.%V alloy was studied as a function of aging conditions. The peak-aged condition retained the corrosion resistance while it deteriorated in the over-aged condition. Nonetheless, the corrosion resistance of the ball-milled Al alloys in all the aging conditions was superior to that of pure Al. The passive film structure and origin of corrosion were studied using scanning/transmission electron microscopy (S/TEM). The high corrosion resistance of the alloy was attributed to the V enrichment at the film/metal interface and deposition of V on the cathodic phases, which suppresses the dissolution of Al within the pit and therefore promotes repassivation in the early stages of corrosion. Graphical abstract: Image, graphical abstract