Mechanical Behavior and Microstructure Evolution of Al-Cu-Li Alloy during Multi-Pass Hot Deformation

作者：Yang Shengli^*; Shen Jian; Li Xiwu; Yan Xiaodong; Zhang Yongan; Li Zhihui; Huang Shuhui; Xiong Baiqing

来源：Rare Metal Materials and Engineering, 2017, 46(10): 2825-2830.

DOI：10.1016/s1875-5372(18)30014-6

• flow stress
• dynamic softening
• static softening
• dynamic precipitation

Continuous, discontinuous, double-pass and multi-pass hot isothermal compression tests were conducted to understand the mechanical behavior and microstructure evolution of the Al-2.5Cu-1.58Li-0.3Mn-0.12Zr-0.06Mg-0.05Ti (wt%) alloy. The tests were conducted at temperature of 420 degrees C and strain rates of 0.001, 0.1 and 10 s(-1) on Gleeble-1500. EBSD and TEM were used to investigate microstructure evolution at different deformation stages of the alloy. Double-pass hot deformation results show that the extension of interval time between two passes is conductive to promoting static softening. It is possible to control the grain size in the test alloy by changing the strain rate at different deformation stages. During multi-pass hot deformation process, static softening between the deformation pass is beneficial to the dynamic softening, vice versa. Dynamic precipitation of T-1 and theta' phase is observed during the multi-pass deformation process (T=420 degrees C, (epsilon) over dot =0.1 s(-1)). In the initial stage of multi-pass deformation, strain-induced dislocations provide the nucleation site for theta' and T-1 phase, promoting their precipitation and coarsening. With increasing of strain, the size of the precipitates T-1 and theta' phase decreases and then tends to be stable, and the density of phase decreases. Flow stress of the test alloy during multi-pass hot deformation is influenced by dynamic softening, static softening and dynamic precipitation.

• 出版日期2017-10
• 单位北京有色金属研究总院