Quantitative atom probe analysis of nanostructure containing clusters and precipitates with multiple length scales

Area of Science:

• Materials Science
• Metallurgy
• Nanotechnology

Background:

• Aluminum-copper (Al-Cu) alloys are critical in aerospace.
• Bimodal microstructures with θ' precipitates and GP zones offer enhanced mechanical properties.
• Understanding solute behavior during deformation is key to optimizing alloy performance.

Purpose of the Study:

• To quantitatively characterize the evolution of GP zones and solute distribution in a bimodal Al-Cu-Sn alloy under plastic strain.
• To investigate the role of GP zones in strengthening mechanisms.
• To explore the repartitioning of copper (Cu) during deformation.

Main Methods:

• Atom Probe Tomography (APT) for high-resolution 3D solute mapping.
• Analysis of GP zone and solute feature evolution as a function of applied plastic strain.
• Application of a novel cluster-finding approach for APT data analysis.

Main Results:

• APT data supports NMR findings of strain-induced GP zone dissolution.
• Significant repartitioning of Cu from GP zones into the solid solution observed.
• Quantitative characterization of the evolution of Cu-containing features in the solid solution.

Conclusions:

• GP zones play a crucial role in the strengthening of Al-Cu alloys.
• Deformation-induced dissolution and solute repartitioning are significant phenomena.
• The study provides detailed insights into microstructure evolution for improved alloy design.