Effects of Changes in Chemistry and Testing Temperature on Mechanical Behavior of Al-Based Amorphous Alloy Ribbons
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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, Tg, and Tx1 in addition to the activation energy for crystallization, whereas the window between Tg and Tx1 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 Tg. Scanning electron microscopy images of fracture surfaces obtained from tests conducted near Tg illustrate ductile rupture and homogeneous flow behavior near the fracture tip.
KeywordsMetallic Glass Amorphous Alloy Slow Strain Rate Amorphous Ribbon Ductile Rupture
The authors thank the DARPA-SAM 2 program for support through Pratt & Whitney Corporation. Supply of materials from Pratt & Whitney and Ames Laboratory is gratefully acknowledged. Useful discussions with A. L. Greer and G. J. Shiflet along with TEM conducted by Dinqiang Li are also appreciated.
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