Superplastic behavior of Al-Cu-Li based alloy
(1.湖南省长沙市中南大学材料科学与工程学院
2.School of Materials Science and Engineering, Central South University, Changsha 410083, China)
2.School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The superplastic behavior was studied in an Al-4Cu-1Li-0.4Mg-0.4Ag-0.1Zr alloy. The alloys were manufactured both by a conventional rolling route and a thermo-mechanical treatment route. The superplastic properties were evaluated as a function of temperature, strain rate, and processing history. Prior to thermo-mechanical processing, the alloys have elevated-temperature ductilities of 94% to 130%, strain rate sensitivities of about 0.25, and activation energies corresponding to lattice diffusion. After thermo-mechanical processing, the alloys have ductilities of 200% to 630%, strain rate sensitivity of about 0.42, and activation energies corresponding to grain boundary diffusion or a mixture of grain boundary diffusion and lattice diffusion. Skipping rapid recrystallization annealing can supply a higher value of elongation-to-failure.
Key words: superplasticity; aluminum-lithium alloy; activation energy; grain boundary diffusion; lattice diffusion; Al-Cu-Li