Contrary to oxide or polymeric glasses, metallic glasses are infamously known for their relatively limited thermal stability, which is often characterized by their narrow supercooled liquid regions. Nonetheless, we successfully fabricated metallic-glass based nanomembranes with an ultrahigh thermal ability by a polymer surface buckling enabled exfoliation technique. These nanomembranes exhibit a distinctive nanostructure with nanosized metallic-glasses encapsulated within an interconnected nanoamorphous-oxide network. Due to a pronounced nanoconfinement effect, crystallization is significantly suppressed. Consequently, these oxidized metallic-glass nanomembranes initiate a glass transition at 324 K at a heating rate of 10 K/min. Remarkably, they also showcase an expansive supercooled liquid region of 448 K, surpassing various metallic and oxide glasses reported. Furthermore, these nanomembranes not only exhibit a low elastic modulus but also achieve superplasticity even at room temperature. This unique blend of thermomechanical properties positions our metallic-glass based nanomembranes as an ideal candidate for nanofabrication processing, such as nanoimprinting, for the creation of next-generation nanodevices.
Keywords: glass transition; heterogeneity; metallic glass; nanoconfinement; thermal stability.