Incorporation of ultrafine nanograins in Zr-Cu-Al-Ni-Co bulk metallic glass enabling significantly improved mechanical properties

The Zr₆₅Cu_17.5Al_7.5Ni₃Co₇ bulk metallic glass (BMG) can be used as engineering material due to its higher glass-forming ability (GFA) and lower toxicity than the typical Zr₆₅Cu_17.5Ni₁₀Al_7.5 BMG. Its widespread application, however, is limited by the inferior compressive plasticity at ambient temperature. Herein, with the aim of improving the mechanical properties of Zr₆₅Cu_17.5Al_7.5Ni₃Co₇ BMG at ambient temperature, annealing of the as-cast alloy at temperatures under the glass transition temperature (T _g) for 0.5 h, 1.0 h and 2.0 h is synthesized. The nanocrystallites formed in the alloys annealed contribute to the significant improvement of mechanical properties. The alloy annealed for 0.5 h exhibited the largest compressive fracture strength of 1908 MPa and plasticity of 14.6%, which are larger than 1643 MPa and 3.0% of the as-cast Zr₆₅Cu_17.5Al_7.5Ni₃Co₇ amorphous alloy, indicating that it can be used as engineering materials for the industrial applications.