High-temperature bulk metallic glasses developed by combinatorial methods.

Area of Science:

• Materials Science
• Metallurgy
• Solid State Physics

Background:

• Metallic glasses offer superior mechanical properties compared to conventional alloys.
• High glass transition temperatures are desirable for high-temperature applications.
• Limited thermoplastic formability in existing high-temperature metallic glasses restricts practical use.

Purpose of the Study:

• To design and discover novel bulk metallic glasses with enhanced high-temperature properties.
• To overcome the limitations of narrow supercooled liquid regions in existing metallic glasses.
• To develop a practical approach for identifying new metallic glass compositions with desirable characteristics.

Main Methods:

• Design of iridium/nickel/tantalum (Ir-Ni-Ta) based metallic glasses, including boron variants.
• Utilized a simplified combinatorial approach correlating glass-forming ability with electrical resistivity.
• Characterized glass transition temperature, supercooled liquid region, mechanical strength, and glass-forming ability (critical casting thickness).

Main Results:

• Developed Ir-Ni-Ta-(B) metallic glasses with a glass transition temperature up to 1,162 K and a 136 K supercooled liquid region.
• Achieved high strength of 3.7 GPa at 1,000 K, surpassing existing alloys.
• Demonstrated a critical casting thickness of 3 mm, enabling thermoplastic forming of small-scale components.

Conclusions:

• The newly designed metallic glasses exhibit exceptional high-temperature strength and improved thermoplastic formability.
• The combinatorial approach using electrical resistivity is an effective, non-destructive method for discovering new metallic glasses.
• This research paves the way for developing advanced metallic glasses for high-temperature and harsh environment applications.