Superplastic characterization of 2095 Al-Li alloy processed by equal channel angular extrusion

摘要

The superplastic behavior of 090 (Al-Cu-Li-Mg-Ag-Zr) alloy has been investigated. The material was processed byequal channel angular extrusion (ECAE) with the intent ofproducing an ultra-fine submicron grained (SMG) structure. Theeffect of warm rolling (WR) on the superplastic response of theECAE processed alloy was assessed. The rate-controllingdeformation mechanisms for the different thermomechanicalprocessing (TMP) conditions were characterized by step-strain rtetests. The rate-controlling deformation mechanism was assessed bycomparing the experimental creep rates with the Sherby model forSMG structures. The ECAE and the ECAE + warm rolled (WR)processed material exhibited percent elongation-to-failure >400percent with strain rate sensitivities (m) of 0.38 at 490 deg C and0.44 at 450 deg C respectively at a stain rte of 2×10~ (-3) s~ (-1).The ECAE processed alloys had activation energies correspondingto lattice diffusion, while the ECAE+ WR processed alloys hadactivation energies corresponding to grain boundary diffusion.