The effects of the addition of 0.29 wt% Ce on the high-temperature mechanical properties of an Al-Cu-Li alloy were investigated. Ce addition contributes to T1 (Al2CuLi) phase coarsening inhibition and Ce-containing intermetallic refinement which greatly improved the thermal stability and high-temperature deformation uniformity of this alloy. On the one hand, small Ce in solid solution and segregation at phase interface can effectively prevent the diffusion and convergence of the main element Cu on T1 phase during thermal exposure. Therefore, the thermal stability of Ce-containing alloy substantiality improves during thermal exposure at the medium-high-temperature stage (170 °C to 270 °C). On the other hand, the increment of the tensile elongation in Ce-containing alloy is much greater than that in Ce-free alloy at high temperatures tensile test, because the refined Al8Cu4Ce intermetallic phase with high-temperature stability are mainly located in the fracture area with plastic fracture characteristics. This work provides a new method for enhancing high-temperature mechanical properties of Al-Cu-Li alloy which could be used as a construction material for high-temperature structural components.
Keywords: Al–Cu–Li alloy; cerium; intermetallic; microstructure; thermal stability.