Effect of Rolling Reduction per Pass on Microstructure and Mechanical Properties of 2197 Al-Li Alloy

Aiming at the poor ductility, toughness and formability of Al-li alloy, the effect of per-pass reduction on microstructure and mechanical properties of 2197 Al-Li alloy were studied by OM/SEM microstructure analysis, tensile properties and hardness/conductivity test, with a constant total reduction of 75%. The results show that the grain structure, the amount and distribution of precipitates are significantly affected by per-pass reduction. The strength of as-rolled alloy increases significantly with the increase of per-pass reduction, while the ductility and toughness decrease obviously. After T8 aging treatment, a large amount of precipitates are produced and the PLC (Portevin-Le Chatelier phenomenon) effect in the rolled alloy is eliminated. The mechanical properties of the alloy rolled by light and heavy reduction improve significantly. After aging treatment, as-rolled alloy with heavy reduction exhibits the optimal comprehensive mechanical properties with tensile strength of 384.94 MPa and the elongation to fracture of 12.45%, which are 2%, 21% and 29%, 31% higher than those of the light and middle reduction alloys, respectively.