Effects of large strain pre-deformation on creep age behavior and microstructural evolution of an Al-Cu-Li alloy

The creep age behaviors and tensile properties of an Al-Cu-Li alloy pre-deformed by cold-rolling with different reductions were tested, combined with the characterization of their microstructural evolution during creep age tests. It is shown that increasing the pre-deformation can bring large number of dislocations into the lattice. These dislocations can detach from the pinning effect of strengthening precipitates under stress field. Thus, the creep strain is promoted by dislocation motion mechanism and the strength increases from 500.2 MPa to 567.8 MPa due to dislocation hardening effect. Further increasing total reduction to 75% makes creep strain increase from 0.14% to 0.24%, which is suggested to be a result of decreasing hindrance effect on dislocation movement due to severe serrations to sub-grain scale in grain boundaries.

Automated summary

The creep age behaviors and tensile properties of an Al-Cu-Li alloy pre-deformed by cold-rolling were investigated. Increasing the pre-deformation promoted the creep strain by dislocation motion mechanism, leading to an increase in strength due to dislocation hardening effect. A further increase in total reduction to 75% resulted in increased creep strain, which was suggested to be a result of decreased hindrance effect on dislocation movement due to serrations in grain boundaries.