Regulating the microstructure and mechanical properties in cast Al–3Li–2Cu-0.15Zr alloy via Sn addition and heat treatment

• DOI: 10.1016/j.jmrt.2024.01.079
• Publication Date: 2024-01-10T02:42:55Z
• Authors: Lixiong Shao; Xianfeng Li; Gaoqiu Sun; Zhiyong Gao; Cunjuan Xia; Haowei Wang
• Keywords: Mining engineering. Metallurgy; Precipitation behavior; TN1-997; Cast Al–Li–Cu alloy; 02 engineering and technology; Sn element; 0210 nano-technology; Mechanical property; Microstructure

The cast Al–3Li–2Cu-0.15Zr alloy is a promising material due to its high strength-to-weight ratio and stiffness. In this work, the Sn addition heat treatment were employed regulate microstructure mechanical properties. results indicate that exists in matrix as solute atoms Sn-rich particles including Li5Sn2, Li13Sn5, Li7Sn2, Li22Sn5. number of these increases content rises. significantly enhances grain refinement, reducing average size 50.2 μm when 0.3wt% incorporated. During aging process, δ′ δ'/β′ precipitates gradually grow coarsen, while T1 θ′ nucleate grow. Some attach board form sandwich-like phases, such δ'/T1/δ′ δ'/θ'/δ'. promotes nucleation precipitates. This achieved by leveraging sites utilizing decrease interface energy between α-Al. Moreover, with vacancy binding reduction temperature can effectively diffusion rate Li vacancies, thereby inhibiting broadening δ′-PFZ. After suitable treatment, Sn-modified Al–Li exhibits characterized fine equiaxed grain, uniform precipitates, narrow δ′-PFZ, contributing excellent properties alloy. Significantly, underlying mechanisms behind aforementioned observations discussed analytically.