The anodic behavior of pure aluminum during straining at a constant potential in various electrolytes was studied. In sodium sulfate solutions, up to 1.84V, and both in sodium chloride solutions and in sodium nitrate solutions below the pitting potential, the exposure of bare metal to the solution leads to repassivation. At potentials higher than the pitting potential, pitting localization depends on the rate of pitting nucleation. Under conditions of fast pitting nucleation generalized pitting was observed, while under conditions of slow pitting, pits nucleated preferentially on the slip lines and might eventually have led to transgranular stress corrosion cracking. Pitting is the result of localized acidification on the metal‐solution interphase due to metal dissolution and hydrolysis of the metal ions. To maintain such acidification, compensation for the loss of protons by hydrogen evolution and by diffusion to the bulk of the solution is necessary. Such compensation will occur if the electrode potential of the metal is higher than its corrosion potential in the locally acidified solution. No pitting will propagate at or below that corrosion potential, which is, for aluminum in chloride solutions, −0.64V.