Effects of pre-deformation mode and strain on creep aging bend-forming process of Al-Cu-Li alloy
(1. Light Alloy Research Institute, Central South University, Changsha 410083, China;
2. State Key Laboratory of High Performance and Complex Manufacturing, Central South University, Changsha 410083, China;
3. Kunming Metallurgical Research Institute, Kunming 650031, China;
4. State Key Laboratory of Pressure Hydrometallurgical Technology of Associated Nonferrous Metal Resources, Kunming 650031, China)
2. State Key Laboratory of High Performance and Complex Manufacturing, Central South University, Changsha 410083, China;
3. Kunming Metallurgical Research Institute, Kunming 650031, China;
4. State Key Laboratory of Pressure Hydrometallurgical Technology of Associated Nonferrous Metal Resources, Kunming 650031, China)
Abstract: The bending deformation method was adopted to characterize the creep deformation behavior of Al-Cu-Li alloy in the creep aging forming (CAF) process based on a series of CAF tests, and the evolution laws of its mechanical properties and microstructures under different pre-deformation conditions were studied. The results show that the bending creep strain characterization method can intuitively describe the creep variation. With the increase of the pre-deformation strain, the creep strain of the specimen firstly increases and then decreases. The increase of the pre-deformation strain can promote the course of aging precipitation, and improve the formed alloy’s tensile properties at room temperature, the Kahn tearing properties, and the fatigue propagation properties. Pre-rolled specimens produce a slightly weaker work hardening than pre-stretched specimens, but they also create a stronger aging-strengthening effect; thus the strength, toughness and damage performance can be improved to some extent. Among all the types of specimens, the specimen with 3% rolling after CAF treatment has the best comprehensive mechanical properties.
Key words: Al-Cu-Li alloy; creep aging forming; pre-deformation; bending creep strain; microstructure evolution; mechanical properties