Effect of Cu/Li Ratio on Porosity and Microstructural Evolution of Gravity and Squeeze-Cast Al–Cu–Li Alloys

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Process metallurgy and materials processing science, 2024-04, Vol.55 (2), p.1117-1133
• Main Authors: Manojkumar, S., Agarwal, Ashish Kumar, Roy, Tushar, Mehta, K. K.
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum base alloys; Casting alloys; Characterization and Evaluation of Materials; Chemistry and Materials Science; Computed tomography; Crystallography; Evolution; Homogenization; Materials Science; Metallic Materials; Nanotechnology; Original Research Article; Porosity; Precipitates; Production methods; Squeeze casting; Structural Materials; Surfaces and Interfaces; Thin Films
• ISSN: 1073-5615; 1543-1916
• DOI: 10.1007/s11663-024-03028-y

The present study investigates the effect of the Cu/Li ratio on the porosity and microstructural evolution of two Al–Cu–Li alloys manufactured through gravity and squeeze-cast routes. The alloy with Cu/Li ~ 4 exhibits a unique compositional segregation pattern and a higher degree of preferred crystallographic orientation than the alloy with Cu/Li ~ 2, regardless of the manufacturing method (gravity or squeeze cast). A specific segregation pattern in alloy with Cu/Li ~ 4 occurs due to the preferential precipitation of Cu-rich Al 2 Cu and Al 2 CuLi precipitates and strong texture along the component { 113 } ⟨ 5 8 ¯ 1 ⟩ . Homogenization of gravity and squeeze-cast alloys reduces segregation, but the alloys produced through the squeeze-cast route have more capability to reduce segregation. The alloy with a Cu/Li ratio ~ 4 displays less response to the post-cast homogenization treatment than the alloy with a Cu/Li ratio ~ 2. The X-ray micro-computed tomography study reveals that the Cu/Li ratio greatly influences the internal and surface porosities, and it is higher for the gravity-cast alloy with Cu/Li ~ 2 than Cu/Li ~ 4. Squeeze casting helps to eliminate most of the porosities in alloys with a Cu/Li ~ 2 but leaves a considerable number of porosities in alloys with a Cu/Li ~ 4.