Novel Ultralight-Weight Complex Concentrated Alloys with High Strength.

Area of Science:

• Materials Science
• Metallurgy
• Alloy Design

Background:

• Complex concentrated alloys (CCAs) are increasingly important for advanced applications.
• Developing ultralight-weight CCAs (ULW-CCAs) with a combination of high strength, low modulus, and good ductility remains a significant challenge.
• Existing CCAs often struggle to balance these properties effectively.

Purpose of the Study:

• To design and explore novel ULW-CCAs.
• To investigate the potential of low-density and low-modulus elements (Al, Li, Mg, Ca, Si, Y) in CCA development.
• To achieve a new class of materials with enhanced specific strength and ductility.

Main Methods:

• Alloy design based on low-density and low-modulus elements.
• Systematic exploration and composition adjustment of Al-Li-Mg-Si-Ca-Y systems.
• Characterization of mechanical properties, including specific strength and compressive plasticity.

Main Results:

• Successful development of an Al$_{19.9}$Li$_{30}$Mg$_{35}$Si$_{10}$Ca₅Y$_{0.1}$ (at %) CCA with a specific strength of 327 KPa·m$^{-3}$.
• Optimized compositions, such as Al$_{15}$Li$_{35}$Mg$_{48}$Ca₁Si₁, Al$_{15}$Li$_{38}$Mg$_{45}$Ca$_{0.5Si$_{1.5}$, and Al$_{15}$Li$_{39}$Mg$_{45}$Ca$_{0.5Si$_{0.5}$ CCAs, exhibited excellent compressive plasticity (>45% and >60%).
• The developed ULW-CCAs demonstrate a superior combination of high specific strength, good ductility, and low Young's modulus compared to previously reported CCAs.

Conclusions:

• Novel ULW-CCAs with a desirable balance of high specific strength, good ductility, and low Young's modulus have been successfully developed.
• The strategic use of specific low-density and low-modulus elements enables the creation of advanced lightweight alloys.
• These findings pave the way for new applications requiring high-performance lightweight materials.