Mechanical properties, glass transition temperature, and bond enthalpy trends of high metalloid Fe-based bulk metallic glasses

Mechanical properties and glass transition temperatures (Tg) of Fe-Cr-Mo-P-C-B bulk metallic glasses containing up to 27 at. % metalloids have been studied. The shear modulus (G) is found to decrease with increasing metalloid content and a maximum plastic strain of ∼3% is obtained, despite the increase in the number of strong metal-metalloid bonds. Also, Tg increases with the decrease in G, in contrast to usual behavior. By employing first-principles calculations, the results are discussed in light of atomic bonding and connectivity in the amorphous network. The findings are relevant to understanding ductility and glass transition of metallic glasses