Molybdate inhibition of corrosion fatigue crack propagation in precipitation hardened Al-Cu-Li

► MoO42- inhibits EFCP in C47A-T86, as understood by film rupture-H embrittlement. ► MoO42- eliminates the effect of environment at low frequencies in C47A-T86. ► MoO42- inhibition destabilizes alloy-induced inhibition in Al-Cu alloys. ► Anodic polarization increases range over which effect of environment eliminated.