Effect of composition on microstructure and properties of as-cast 2196 Al–Cu–Li alloy

ABSTRACT

The influence of Li, Mg and Ag on microstructure and properties of Al–Cu–Li alloys attracted great attention, while few reports on casting state. In fact, the as-cast condition greatly influences the microstructure and performance during later treatments. This study conducts casting experiments on 2196-based Al–Cu–Li alloys with different Li, Mg and Ag additions. The grain refinement, evolution of intermetallic phases, and modification of properties caused by the composition are investigated by OM, EBSD, SEM, TEM characterisation and mechanical testing. In particular, microstructural, microchemical and crystallographic characteristics of intermetallic phases are identified. The mechanism based on the compositional effect on microstructure evolution is clarified, in combination with thermodynamic calculation. The mechanism of modification of properties is discussed in relation to the microstructure variations.

KEYWORDS:

• Al–Li alloy
• casting
• compositon design
• chracterisation
• microstructure
• precipitation
• mechanical properties
• thermodynamic calculation

Acknowledgements

This work was performed at the USTB University of Science and Technology Beijing. Chen K and Wang Z designed the project. Tian Y produced the materials. Chen K, Li Z, Cao Y, and Wu X performed the mechanical testing and microstructural characterisation. Chen K and Pan S contributed to the theoretical analysis. Chen K wrote the manuscript with support from Chen X. All authors contributed to the discussion of the results and commented on the manuscript.

Data availability statement

All data are available from the corresponding authors on reasonable request.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Beijing Municipal Natural Science Foundation [grant number 2214072], the National Natural Science Foundation of China [grant numbers 52101119, 51971031], the Young Elite Scientist Sponsorship Program by CAST [grant number YESS20210139], the Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities) [grant number FRF-IDRY-20-034], Fundamental Research Funds for the Central Universities [grant number 00007490], and the Domain Foundation of Equipment Advance Research of 13th Five-year Plan [grant number 61409220124].