预处理对喷射沉积Al-Cu-Li合金中Al3Zr粒子析出及再结晶行为的影响

1 Introduction

Al-Cu-Li alloys, which have excellent mechanical properties, have been rapidly developed in recent years and are considered as ideal lightweight structural materials [1-3]. However, Al-Cu-Li alloys are prone to recrystallize during the hot deformation process to form coarse grains and reduce their mechanical properties [4]. Zirconium (Zr) is added to aluminum alloys to form Al3Zr dispersoids, which can inhibit the degree of recrystallization and improve mechanical properties because the grain boundaries, subgrain boundaries, and dislocation motion can be effectively pinned by fine Al3Zr particles [5-7]. However, the low solubility, high lattice misfit, and slow diffusion rate of Zr atoms in the Al matrix result in severe microsegregation of the Zr solute. The dendrite core is enriched in Zr, while a much lower concentration is present toward the dendrite edge [8-9]. Compared with the traditional casting process, spray-deposited technology with rapid cooling and solidification avoids severe segregation during casting. The spray-deposited alloy ingots are composed of equiaxial grains, with a lower degree of microsegregation and a more uniform microstructure [10-12].