Concurrently improving uniform elongation and strength of ultrafine-grained Al–2Li alloy

Abstract High-strength ultrafine-grained Al–2Li (wt.%) alloy produced by accumulative roll bonding (ARB) process possessed poor uniform elongation, indicating that the ultrafine-grained Al–2Li alloy was susceptible to the inhomogeneous deformation (necking) and insufficient strain hardening. Through these strategies for designing and tailoring different microstructure: 1) suppressing recovery and recrystallization by cryogenic rolling, 2) forming a bimodal grain size by strain gradient distribution and 3) precipitating Al3(Zr, Li) particles by introducing Al–2Li-0.1Zr layers, the simultaneous improvement in uniform elongation and strength of ultrafine grained Al–2Li alloy was achieved. The ultimate tensile strength (UTS) of ultrafine grained Al–2Li alloy was further improved from 300 MPa to 380 MPa by the combination of a bimodal grain size distribution and Al3(Zr, Li) precipitates, meanwhile, the uniform elongation was significantly increased from 2.8% to 8.4%.