Evolution of microstructure and properties during homogenization of the novel Al–Li alloy fabricated by electromagnetic oscillation twin-roll casting

Abstract

As a new non-traditional method of alloy preparation, the electromagnetic twin-roll casting (ETRC) technology overcomes the defects of traditional technologies in the preparation of traditional aluminum alloy, especially Al–Li alloy, such as gas hole in the traditional mold casting and macro segregation in the twin-roll casting (TRC) process, which greatly improves the comprehensive properties of the alloy strip. In present work, the evolution of microstructure and properties of Al–Li alloy fabricated by copper mold casting, and TRC and ETRC processes during homogenization have been investigated in detail. Under the action of electromagnetic field, the secondary dendrite arm spacing (SDAS) of the alloy reduces significantly and the solidification structure of the alloy refines dramatically. Moreover, the volume fraction of non-equilibrium eutectic phases and intermetallics which continuously distributes in the interdendritic region and grain boundaries decreases remarkably, and the dendritic network as well as the microsegregation of the alloying elements eliminates effectively. Therefore, compared with the traditional technologies, the homogenization time of the alloy fabricated by ETRC is greatly shortened, which provides a new idea for the short process and efficient preparation of Al–Li alloy.