Influences of Quenching rate on Mechanical and Corrosion Properties of Al-Cu-Li Alloy

The study investigated the influence of the quenching rate on the mechanical and corrosion properties of Al-Cu-Li alloys through immersion end-quenching experiments, tensile properties tests, intergranular corrosion (IGC) tests, and microstructure characterization. The research results show that a decrease in the quenching rate leads to substantial precipitation and growth of the quenching-induced θ and T1 phases. This process consumes Cu atoms within the matrix, leading to a reduction in the precipitation of the T1 strengthening phase during the aging process, which in turn decreases the strength. Meanwhile, there is a rise in the amount of quenching-induced T1 phases at (sub)grain boundaries ((S)GBs) and the width of the precipitate-free zone (PFZ) at GBs. This leads to preferential corrosion along the (S)GBs, which causes corrosion to propagate deeper along the (S)GBs. Additionally, a large number of the quenching-induced T1 phases are present within the grain, resulting in corrosion extension within the grain and subsequently decreasing the corrosion properties of the alloy.