Low-density to high-density transition in Ce75Al23Si2 metallic glass

Area of Science:

• Materials Science
• Condensed Matter Physics
• Amorphous Materials

Background:

• Metallic glasses exhibit unique properties due to their disordered atomic structure.
• Polyamorphism, the existence of multiple amorphous states, is a key phenomenon in some glasses.
• Understanding pressure-induced transitions is crucial for tailoring material properties.

Purpose of the Study:

• To investigate the effect of minor silicon doping on the polyamorphic transition in Ce-Al-Si metallic glass.
• To analyze the thermal stability of different amorphous phases under varying pressure conditions.
• To explore the potential of minor alloying for controlling polyamorphism in metallic glasses.

Main Methods:

• In situ high-pressure X-ray diffraction (XRD) to observe pressure-induced transitions.
• In situ high-temperature and high-pressure XRD to study thermal stability.
• Comparative analysis of Ce(75)Al(23)Si(2) and Ce(75)Al(25) metallic glasses.

Main Results:

• A pressure-induced polyamorphic transition from low-density amorphous (LDA) to high-density amorphous (HDA) state was observed at approximately 2 GPa.
• Minor Si doping shifted the transition pressure and enhanced the thermal stability (onset crystallization temperature, T(x)) of both LDA and HDA phases.
• Different pressure dependencies of T(x) were observed for LDA and HDA states, with a turning point around 2 GPa.

Conclusions:

• Minor alloying, specifically Si doping, can create new polyamorphous metallic glass systems.
• Silicon doping modifies the polyamorphic transition pressure and stabilizes amorphous phases.
• This study provides insights into controlling polyamorphism and properties of metallic glasses through minor alloying.