Simultaneously improving strength, ductility and formability in 2195 Al-Li alloy components via pre-aging treatment

¹ State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Ploytechnical University, Xi’an 710072, China
² Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment, School of Materials Science and Engineering, Northwestern Ploytechnical University, Xi’an 710072, China

^* Corresponding author: skk0104@163.com

Abstract

The Al-Cu-Li alloy large thin-walled complex components are crucial for the critical equipment in aerospace and aviation fields due to their high-performance, lightweight and high-efficiency. However, the poor plasticity of Al-Cu-Li alloy sheets limits the forming of large thin-walled complex components. Herein, an effective strategy for simultaneously enhancing strength, ductility and formability of rolled Al-Cu-Li alloy sheets is proposed by short time artificial pre-aging after solution treatment. The result indicates that good ductility is obtained through pre-aging treatment, with elongation increased by 24.2% compared to the solution alloy. Notably, carrying out formability tests, the limiting bulging height (LDH) of preaged alloy (37.905mm) is increased by 20.5% compared to solution alloy (31.468mm), and meanwhile surface roughness is improved from 3.339µm to l.392µm. Achieving higher limit drawing ratio (LDR=2.628) and average plastic ratio (r̄=1.55) enhances the drawability of the Al-Cu-Li alloy sheets. Microstructure analysis reveals that the simultaneous increase in strength, ductility and formability is attributed to the fine and well-dispersed coherent nanoprecipitates, interacting with dislocations, weaking local stress concentration, serving as dislocation sources, promoting dislocation movements. These findings offer valuable insights for developing high-performance Al-Cu-Li alloy complex components.