Microstructure Evolution and Mechanical Properties of 16-Layer 2195 Al-Li Alloy Components Manufactured by Additive...

Area of Science:

• Materials Science
• Metallurgy
• Additive Manufacturing

Background:

• Additive friction stir deposition (AFSD) involves repeated thermal cycles, complicating microstructural evolution in multi-layer alloys.
• Understanding these thermal effects is crucial for optimizing mechanical properties in additively manufactured components.

Purpose of the Study:

• To systematically investigate the microstructure and mechanical property variations across different layers of a 16-layer 2195 alloy component fabricated by AFSD.
• To determine the impact of repeated thermal cycling on phase precipitation and mechanical performance.

Main Methods:

• Fabrication of a 16-layer 2195 alloy component using Additive Friction Stir Deposition (AFSD).
• Microstructural analysis of distinct regions: last, intermediate, and first deposited layers.
• Mechanical property testing, including microhardness, yield strength, ultimate tensile strength, and elongation.

Main Results:

• Minimal T1-phase was observed only in the last deposited layers.
• The θ'-phase formed complex precipitates with δ' and β' phases due to thermal cycling.
• A clear gradient in mechanical properties was observed, with decreasing strength and hardness from the top (last layers) to the bottom (first layers).

Conclusions:

• Repeated thermal cycling during AFSD significantly influences the phase evolution and precipitate characteristics in 2195 alloy.
• The resulting microstructural gradient directly correlates with mechanical property variations, with the highest properties observed in the topmost layers.