Balancing strength and ductility of LA141 alloy with a micro-nano laminated structure

The laminated LA141 sheets were processed by the accumulative roll bonding (ARB). The interaction between dislocations and laminated interfaces, and the effect of bond interface spacing on the dynamic recrystallisation (DRX) behavior and mechanical properties were investigated. The results show that, with the increase of ARB cycles, physical metallurgical bonding is enhanced. MgLi₂Al nanophases and fragmented MgO particles are formed at the bond interface during ARB process, which has a significant positive effect on the interface bonding. With the increase of ARB cycles, the bond interface spacing decreases, DRX mode changes from continuous dynamic recrystallization (CDRX) to geometrical dynamic recrystallization (GDRX), and the Zener-pinning effect is enhanced, which facilitates the grain refinement strengthening. The bond interface can not only effectively hinder the movement of dislocations causing strengthening, but also absorb, reflect and transmission the dislocations causing the improvement of the ductility. The final LA141 alloy possesses a tensile strength of 247 MPa and an elongation of 16.6 %, of which is 93.0 % and 70.3 % higher than the as-cast alloy, respectively.