ELECTRONIC STRUCTURE AND PHASE STABILITY OF GLASSY ALLOYS

摘要

The electronic structure and phase stability of the Zr-Ni-Al ternary glassy alloys, have been systematically investigated experimentally and theoretically. Thermal stability and crystallization process have been clarified by the DSC and XRD measurements. Composition dependence of the stability parameter; T_g/T_l has been clarified. The electronic structure around the Fermi level has been investigated by using the high resolution UPS. It is found that there is a sizable pseudogap at the Fermi level of the electronic structure of the Zr_(65)Ni_(20)Al_(15) glassy alloy. The DVXa calculations for the charateristic clusters in the Zr-Ni-Al glassy alloy having high glass forming ability have been also performed. It is found that these clusters formation reduces the internal energy and can contribute to the phase stability. The LMTO-ASA band calculations for the Zr_6NiAl_2 compound which is the most relevant compound to the Zr_(60)Ni_(25)Al_(15) glassy alloy have been also performed. It is found that there is a sizable pseudogap at the Fermi level in its electronic structure, suggesting exiting of the pseudogap of the glassy alloy.