Through‐Thickness Inhomogeneity on Microstructure, Mechanical Properties, and Corrosion Resistance of Al–Cu–Li Alloy Thick Plate

The relationship between mechanical properties, corrosion resistance, and microstructure inhomogeneity along the thickness direction of an aerospace‐grade Al–Cu–Li alloy thick plates were evaluated. The results showed a progressive enhancement in mechanical properties from surface layer through T/4 layer and then to T/2 layer. The strength increased from 578 MPa to 607.7 MPa and then to 649.7 MPa. The IGC degree of Al–Cu–Li alloy thick plates decreased gradually from the surface layer to T/2 layer. The texture at the surface layer mainly consisted of recrystallization texture, shear texture, and a small amount of deformation texture. The texture at the T/2 layer was mainly the deformation texture. The main precipitation phase of the alloy after T86 aging was T 1 phase, with small amounts of θ’ and δ’ phases. A distinct density gradient of T 1 phase was observed along the thickness, progressively increasing from surface layer to T/4 layer and reaching maximum in T/2 layer. The combined effect of texture characteristics and aging precipitates, the mechanical properties, and corrosion resistance of T/2 layer were better than surface layer.