A high-specific-strength and corrosion-resistant magnesium alloy.

Area of Science:

• Materials Science
• Metallurgy
• Corrosion Science

Background:

• Achieving high strength, ductility, and corrosion resistance simultaneously in lightweight alloys is challenging.
• Traditional magnesium (Mg)-based alloys often exhibit poor corrosion resistance.
• Optimizing these properties is crucial for demanding sectors like automotive and aerospace.

Purpose of the Study:

• To design and develop an ultra-lightweight alloy with enhanced strength, ductility, and corrosion resistance.
• To investigate the microstructural basis for the improved properties of Mg-Li alloys.
• To provide a superior alternative to existing lightweight materials.

Main Methods:

• Development of a Li-rich Mg-Li-based alloy with an ultralow density of 1.4 g cm⁻³.
• Utilizing a combination of extrusion, heat-treatment, and rolling processes.
• Characterization of the alloy's microstructure, focusing on solute nanostructure within a body-centred cubic matrix.

Main Results:

• The developed Mg-Li alloy exhibits high strength and ductility.
• It demonstrates significantly improved corrosion resistance compared to conventional Mg-based alloys.
• A uniform lithium carbonate film, offering greater surface coverage, is identified as the reason for enhanced corrosion protection.

Conclusions:

• The novel Mg-Li alloy successfully overcomes the inverse correlation between strength, ductility, and corrosion resistance.
• The unique solute nanostructure and protective lithium carbonate film contribute to its superior performance.
• This alloy presents a promising candidate for applications requiring lightweight, high-performance materials.