Effects of Changes in Chemistry and Testing Temperature on Mechanical Behavior of Al-Based Amorphous Alloy Ribbons

The effects of changes in composition, testing temperature, strain rate, and thermal exposure on the flow behavior of a series of Al-Gd-Ni-X amorphous alloy ribbons have been determined via hot microhardness and tension testing. It is shown that the addition of Fe, Co, and Fe/Co combination into these materials increases the strength, T_g, and T_x1 in addition to the activation energy for crystallization, whereas the window between T_g and T_x1 remains similar. The uniaxial tensile tests show these ribbons exhibit a high strength, around 1 GPa, at room temperature (RT), and the results also show that these ribbons maintain their strength, nearly 45 pct of their RT value, at temperatures near T_g. Scanning electron microscopy images of fracture surfaces obtained from tests conducted near T_g illustrate ductile rupture and homogeneous flow behavior near the fracture tip.