Precipitation and mechanical properties for rapidly solidified Al-Cu-Li alloy: Effect of pre-rolling

Pre-strain deformation before artificial aging is preferred for fabricating high-performance Al-Cu-Li alloy plates. The precipitation and mechanical properties of rapidly solidified Al-Cu-Li alloy as a function of pre -rolling deformation from 4% to 20% were investigated. The increase in pre-rolling deformation leads to higher dislocation density, which provides more nucleation sites for the T1 phase. As a result, higher density and finer diameter of the T1 phase in grains and mitigated enrichment of T1 phase at the subgrain boundaries were obtained. Meanwhile, more T1 phase consumes more Cu atoms, thus suppressing the precipitation of 0' phase. Due to strain hardening and precipitation strengthening, the yield strength of alloy increases with the pre-rolling deformation, reaches a maximum value of 641.6 MPa after 20% pre-rolling. The strength model shows that increasing the pre-rolling deformation leads to a decrease in the strengthening contribution of the T1 phase, which results from the failure of the dislocation bypass me-chanism. While the increase in yield strength is attributed to larger strain hardening from high levels of pre -rolling deformation.(c) 2022 Elsevier B.V. All rights reserved.