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

The amorphous alloy rods of (Zr53Cu30Ni9Al8)100−xSix (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−xSix alloy rods exhibit a typical amorphous diffraction pattern with only a broad maximum around 2θ around 40 degree. Both Tg (glass transition temperature) and Tx (crystallization temperature) of these (Zr53Cu30Ni9Al8)100−xSix alloys increase with the silicon addition. In addition, both the activation energy of crystallization and the incubation time of isothermal annealing these (Zr53Cu30Ni9Al8)100−xSix amorphous alloys indicate that the (Zr53Cu30Ni9Al8)99.25Si0.75 alloy possesses the best thermal stability in the (Zr53Cu30Ni9Al8)100−xSix 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)99.25Si0.75 amorphous alloy.