Stability of a metastable B2 phase embedded in a metallic glass matrix at liquid-nitrogen temperature

We report the unique thermal and mechanical stability of a metastable B2 phase embedded in a metallic glass matrix at liquid-nitrogen temperature. The B2 phase is stabilized by the constraints of the hard amorphous matrix, which result from the increasing hydrostatic pressure during cryogenic cooling. The stability of the B2 phase contributes to the high strength and ductility of CuZr-based bulk metallic glass composites at cryogenic temperature. This discovery is expected to provide new strategies for designing strong and ductile materials containing a metastable phase.