The effect of asymmetric rolling on the microstructure and properties of Al–Cu–Li–TiC/TiB2 alloys

Abstract

The study systematically investigated the impact of asymmetric rolling (AR) and subsequent aging treatment on the microstructure and mechanical properties of Al–Cu–Li–TiC/TiB2 alloy. The average grain size of the as-cast A0 and A1 alloys was 249.87 μm and 38.2 μm, respectively. The grain size was significantly refined by TiC and TiB2 particles. The texture of A0 and A1 samples after symmetric rolling (SR) was dominated by the β-fiber, including typical Copper, S, and Brass rolled textures. The core of the board has a relatively high proportion of Brass texture. The grain size of the AR sheet increases gradually from the surface to the center, with the middle to fast (MF) layer having the largest grain size. The middle to slow (MS) layer has the highest strength of Goss texture, indicating that the shear bands formed by AR are mostly located in the MS layer. A significant amount of T1 precipitate was observed in the aged sample, and a new T1 phase composite with a thickness of 1.426 nm was found in the AR sample. The structure of the composite consists of two parallel T1 precipitates with Al–Cu layer atoms at the center. The growth behavior of the composite is such that the new T1 precipitate adheres to one side of the original T1 precipitate and grows parallel in the form of T1P-T1. In the T85 state, the A0SR samples exhibit a yield strength, tensile strength, and elongation of 503 MPa, 518 MPa, and 7.5%, respectively. The A1-SR samples exhibit a yield strength, tensile strength, and elongation of 520 MPa, 526 MPa, and 8.2%, respectively. The A0-AR samples exhibit a yield strength, tensile strength, and elongation of 553 MPa, 572 MPa, and 4.5%, respectively, while the A1-AR samples exhibit a yield strength, tensile strength, and elongation of 580 MPa, 605 MPa, and 5.2%, respectively. The increase in yield strength can be attributed to fine-grained strengthening, precipitation strengthening, and Orowan strengthening brought about by nano TiC/TiB2 particles.