Effect of quenching rate on the corrosion mechanism of coarse grain and fine grain layer in 2195 aluminum-lithium alloy extruded plates

The present study investigates the exfoliation corrosion (EXCO) mechanism of the surface layer (SL) and central layer (CL) of 2195 aluminum alloy extruded plates under different quenching rates . The results indicate that with a decreasing quenching rate, the EXCO resistance of both SL and CL samples improves, with the EXCO grades reducing from PB and EA to N and PB, respectively. This is contrary to the results of the EXCO quench sensitivity study in 7XXX series aluminum alloys. Furthermore, as the quenching rate decreases, the corrosion depth of SL samples decreases (from 138 to 79 μm) while that of CL samples increases (from 216 to 505 μm). Combined with microstructural characterization, the study elaborates in detail on the EXCO corrosion mechanism of the alloy's SL and CL, providing a theoretical basis for preparing aluminum-lithium alloys with higher corrosion resistance.