Effects of extrusion ratio and temperature on microstructure and mechanical properties of extruded Al-4Cu-1Li-0.4Mg-0.4Ag-0.11Zr alloy

In this work, the effects of extrusion temperature and ratio on the microstructure and mechanical properties of a novel Al-4Cu-1Li-0.4Mg-0.4Ag-0.11Zr alloy were investigated. Results indicate that the softening mechanism during extrusion is primarily dominated by dynamic recovery (DRV). However, the microstructure exhibits significant dynamic recrystallization (DRX) characteristics when the extrusion temperature rises to 480 degrees C. The texture orientation of the extruded rods is concentrated in the < 111 > and < 001 > directions, with < 111 > texture displaying higher intensity. Although variations in extrusion ratio and temperature show a small effect on texture type, they substantially alter texture intensity. After T6 aging treatment, the density of T-1 phase increases with increasing extrusion ratio, accompanied by finer sizes and more uniform distribution. On the other hand, high temperature leads to apparent recrystallization and grain coarsening, inevitably reducing the formability and plasticity. As the extrusion temperature and extrusion ratio were optimized to 440 degrees C and 16:1 respectively, a good combination of strength and ductility was obtained (YS = 650 MPa, UTS = 704 MPa, EL = 7.0 %) after ageing at 175 degrees C for 32 h. This work is expected to provide valuable guidelines for designing novel extruded Al-Cu-Li alloys with broader applications.