Thermal and mechanical properties of the Zr₅₃Cu₃₀Ni₉Al₈ based bulk metallic glass microalloyed with silicon

The amorphous alloy rods of (Zr₅₃Cu₃₀Ni₉Al₈)_100-xSi_x (x = 0.25, 0.5, 0.75, 1) with a diameter of 2-6 mm were prepared by drop casting method in an Ar atmosphere. The thermal properties, including glass forming ability (GFA) and thermal stability during isothermal annealing of these amorphous alloys, and the mechanical properties have been systematic investigated by the combination of DSC, XRD, SEM, TEM, and compression test. The result of X-ray diffraction reveals that these entire (Zr₅₃Cu₃₀Ni₉Al₈)_100-xSi_x alloy rods exhibit a typical amorphous diffraction pattern with only a broad maximum around 2θ around 40 degree. Both T_g (glass transition temperature) and T_x (crystallization temperature) of these (Zr₅₃Cu₃₀Ni₉Al₈)_100-xSi_x alloys increase with the silicon addition. In addition, both the activation energy of crystallization and the incubation time of isothermal annealing these (Zr₅₃Cu₃₀Ni₉Al₈)_100-xSi_x amorphous alloys indicate that the (Zr₅₃Cu₃₀Ni₉Al₈)_99.25Si_0.75 alloy possesses the best thermal stability in the (Zr₅₃Cu₃₀Ni₉Al₈)_100-xSi_x alloy system. In parallel, the result of compression test shows that the yield strength increases with the addition of Si content and reaches to a maximum value about 1750 MPa with 3% plastic strain for the (Zr₅₃Cu₃₀Ni₉Al₈)_99.25Si_0.75 amorphous alloy.