Effect of equal channel angular pressing (ECAP) on the evolution of texture, microstructure and mechanical properties in the Al-Cu-Li alloy AA2195

Abstract

In this study, one of the severe plastic deformation (SPD) techniques, Equal Channel Angular Pressing (ECAP) has been successfully applied to the Al-Cu-Li alloy AA2195 at 250 °C and the development of microstructure, texture and mechanical properties has been studied. A systematic analysis has been carried out by using EBSD and TEM to understand the microstructural features, and the nature of different precipitates presence in the alloy AA2195. Microstructural features indicate considerable grain refinement leading to an average grain size of 2.8 ± 0.7 μm after 4 ECAP passes. Continuous dynamic recrystallization (CDRX) has been identified as the mechanism that leads to the formation of fine grain structure in the alloy AA2195 during the warm ECAP process. TEM results confirm the distribution of strengthening precipitates δ′(Al3Li), β(Al3Zr) and T1(Al2CuLi) in the alloy. The overall texture has become weak after ECAP processing and has been simulated using Visco-plastic self-consistent simulation (VPSC). The evaluation of mechanical properties indicates a substantial increment in hardness, strength properties with a minor reduction of ductility after 4 passes. Low mechanical property anisotropy is expected in the processed AA2195 alloy due to its weak texture.